using credit card and paying back quickly
Yes, however you would have to wait for the $900 to actually be available in your credit card account if making the transaction from an account from another bank or provider, as it usually might take one to two business days for this to happen.  If both the chequing account and credit card account are with the same bank, then usually this will go through straight away, and you will be able to make your next purchase on the same day, but I would check your credit card balance first before making that purchase. "I can't speak for every credit card, but I know two of mine don't have overage fees. The transaction either goes through, or gets denied. Check your card agreement and look for the fee section. One other thing to consider, sometimes when you make an online payment to a credit card, you will notice that the ""Available Balance"" number on the account will increase right away even if the payment is not reflected on your ""Current Balance"". If this is the case, and you are positive that your payment will be successfully posted to the account, I say go for it."
Gaining traction is your first priority. WARNING: as @JosephZambrano explains in his answer the tax penalty for withdrawing from a 401(k) can easily exceed the APR of the credit card making it a very bad strategy. Consult in-depth with a financial advisor to see before taking that path.  As @JoeTaxpayer has noted a loan is another alternative. The 401k is no good to you if you can't have shelter or comfort in the mean time.  The idea is to look at all the money as a single thing and balance it together.  There is no credit and retirement, just a single target that you can hit by moving the good money to clear the bad. Consolidating the credit card debt somehow would be very wise if you can.  Assuming it is 30% APR shrinking that quickly is the first priority. You may be able to justify a hardship withdrawal to finance the reduction/consolidation of the credit card.  It may be worth considering negotiating a closure arrangement with a reduced principal.  Credit card companies can be quite open to this as it gets their money back. You may also be able to negotiate a lower interest rate. You may be able to negotiate a non-credit-affecting debt consolidation with a debt consolidator.  They want to make money and a 25K loan to a person with sound credit is a pretty good bet. Moving, buying a house, or any of that may just relocate the problem.   You may be able to withdraw $25K from your 401k under hardship, pay the credit card, and come up with a payment plan for the medical debt. It's a retirement setback for sure, but retirement is an illusion with that credit card shark eating all of your hard-earned money.  You gotta slay that beast quick. Again, be sure to fully analyze whether the penalty on the 401(k) withdrawal exceeds the APR of the credit card. I do this all the time, my credit rating over time plotted on a graph looks like saw blades going upward on a slope I use a credit alert service to get my credit reports quarterly, and I know when the credit agencies update their files (every three months), so I never have a high balance at those particular times Basically, I use the negative hard pulls to propel my credit score upwards with a the consequentially lowered credit utilization ratio, and the credit history. So here is how it works for me, but I am not an impulse buyer and I wouldn't recommend it for most people as I have seen spending habits: Month 1: charge cards, pay minimum balance (raises score multiple points) Month 2: PAY OFF ALL CREDIT CARDS, massive deleveraging using actual money I already have (raises score multiple points) Month 3: get credit report showing low balance, charge cards, pay minimum balance ask for extensions of credit, AND followup on new credit line offers (lowers score several points per credit inquiry) Month 4: charge cards, pay minimum balance, discretionally approving hard pulls - always have room for one or two random hard pulls, such as for a new cell phone contract, or renting a car, or employment, etc Month 5: PAY OFF CREDIT CARDS using actual money you have. (the trick is to NEVER really go above a 15% credit utilization ratio, and to never overleverage. Tricky because very quickly you will get enough credit to go bankrupt) Month 6: get credit report showing low balances, a slight dip in score from last quarter, but still high continue. A search quickly led to http://www.cardfellow.com/blog/debit-card-credit-card-difference-charges/ which shows the difference in merchant fees charged. A $200 charge costs $3.50-$3.60, a debit charge, $2.34-$2.39 but a PIN Debit, $1.87. The debit cards are a full percent less cost to the merchant, so the money collected is less to use for rewards. (I can't help but wonder how my card gives me 2% cash back, no fee, when I never pay interest.) The whole point of a credit report and, by extension, a credit score, is to demonstrate (and judge) your ability to repay borrowed funds.  Everything stems from that goal; available credit, payment history, collections, etc all serve to demonstrate whether or not you personally are a good investment for lenders to pursue. Revolving credit balances are tricky because they are more complicated than fixed loans (for the rest of this answer, I'll just talk about credit cards, though it also applies to lines of credit such as overdraft protection for checking accounts, HELOCs, and other such products). Having a large available balance relative to your income means that at any time you could suddenly drown yourself in debt.  Having no credit cards means you don't have experience managing them (and personal finances are governed largely by behavior, meaning experience is invaluable).  Having credit cards but carrying a high balance means you know how to borrow money, but not pay it back.  Having credit cards but carrying no balance means you don't know how to borrow money (or you don't trust yourself to pay it back). Ideally, lenders will see a pattern of you borrowing a portion of the available credit, and then paying it down.  Generally that means utilizing up to 30% of your available credit.  Even if you maintain the balance in that range without paying it off completely, it at least shows that you have restraint, and are able to stop spending at a limit you personally set, rather than the limit the bank sets for you. So, to answer your question, 0% balance on your credit cards is bad because you might as well not have them.  Use it, pay it off, rinse and repeat, and it will demonstrate your ability to exercise self control as well as your ability to repay your debts. You can split payments, and nobody judges you because most prepaid cards are actually gift cards.  They just think you have generous friends.   When you use Visa/MC at a vendor, they get dinged around 2-3% plus 35 cents flat-rate.  So when you ask them to charge 77 cents to the card, you're essentially asking they give half of it to Visa/MC.  Which is unfair.  A charity won't turn it down, but it's wasted.  So how do you solve this problem?  If you see a small merchant using Square or PayPal Here, their merchant agreements charge a flat rate (2.75% and 2.70% respectively) with no flat rate per transaction.  If you see they are on PayPal/Square, go for it.   Obviously PayPal itself doesn't have that problem, because they have a really, really good deal with Visa and Mastercard.  So feel free to buy yourself credit on your PayPal account with these residual values.   Amazon probably has a similar deal.   You are getting these small amounts because you aim to pay a $22.69 bill with a card that has $25 on it.  Reasonable, but it causes this.   Flip it around: pay a $22.69 bill with a card that has $20 on it, consume the $20 value, and pay the $2.69 in cash.  You may need to tell the cashier exactly the amount to charge (e.g. $20.00) especially if it is a Visa/MC card.  It will certainly go faster if you do.  The cashier may be able to pull up the balance, but it's an extra procedure, and an inexperienced cashier may struggle with it / have to call the manager etc. - not worth it in my book. "Well, I answered a very similar question ""Credit card payment date"" where I showed that for a normal cycle, the average charge isn't due for 40 days. The range is 35-55, so if you want to feel good about the float just charge everything the day after the cycle closes, and nothing else the rest of the month. Why is this so interesting? It's no trick, and no secret.  By the way, this isn't likely to be of any use when you're buying gas, groceries, or normal purchases. But, I suppose if you have a large purchase, say a big TV, $3000, this will buy you extra time to pay. It would be remiss of me to not clearly state that anyone who needs to take advantage of this ""trick"" is the same person who probably shouldn't use credit cards at all. Those who use cards are best served by charging what they can afford to pay at that moment and not base today's charges on what paychecks will come in by the due date of the credit card bill." There are a couple of things to consider.   First, in order to avoid interest charges you generally just need to pay the statement balance before the statement due date.  This is your grace period.  You don't need to monitor your activity every day and send immediate payments.  If you're being really tight with money, you can actually make a little profit by letting your cash sit in an interest bearing account before you pay your credit card before the due date. Second, credit card interest rates are pretty terrible, and prescribed minimum payments are comically low.  If you buy furniture using your credit card you will pay some interest, be sure to pay way more than the minimum payment.  You should avoid carrying a balance on a credit card.  At 20% interest the approximate monthly interest charge on $1,000 is $16.67. Third, if you carry a balance on your credit card you lose the interest grace period (the first point above) on new charges.  If you buy your couch, and carry the balance, when you buy a soda at 7-11, the soda begins to accrue interest immediately.  If you decide to carry a balance on a credit card, stop using that card for new charges.  It generally takes two consecutive billing period full balance payments to restore the grace period. Fourth, to answer your question, using a credit card to carry a balance has no impact on your score.  Make your payments on time, don't exceed your limits, keep your utilization reasonable.  The credit agencies have no idea if you're carrying a balance or how much interest you're paying. To Appease the people who think point four needs more words: Your credit report contains your limit, your reported balance (generally your statement balance), and approximate minimum payment.  There is no indication related to whether or not the balance contains a carried balance and/or accrued interest.  The mere fact of carrying a balance will not impact your credit score because the credit reporting bureaus don't know you're carrying a balance.  Paying interest doesn't help or hurt your score.  Obviously if your carried balance and interest charges push your utilization up that will impact your score because of the increased utilization. Make your payments on time, don't exceed your limits, keep your utilization reasonable and your score will be fine. Awesome, you are a math guy.  Very good for you.  In theory, what you are proposing, should work out great as the math works out great.  However have you taken a economics or finance coursework?  The math that they do in these class will leave a most math guys uncomfortable with the imprecision even when one is comfortable with chaos theory. Personal finance is worse.  If it were about math things like reverse mortgages, payday lenders, and advances on one income tax returns would not exist.   The risk derived from the situation you describe is one born out of behavior.  Sometimes it is beyond control of the person attempting your scheme.  Suppose one of these happen: In my opinion the market is risky enough without borrowing money in order to invest.  Its one thing to not pay extra principle to a mortgage in order to put that money in play in the market, it is another thing to do what you are suggesting.  While their may be late fees associated with a mortgage payment, a fixed rate mortgage will not change if you late on payment(s). On these balance transfer CC schemes they will jack your rate up for any excuse possible.  I read an article that the most common way to end up with a 23%+ credit card was to start out with a 0% balance transfer.  One thing that is often overlooked is that the transfer fee paid jacks up the stated rate of the card.   In the end, get out of consumer debt, have an emergency fund, then start investing.  Building a firm financial foundation is the best way to go about it.  Without one it will be difficult to make headway.  With one your net worth will increase faster then you imagined possible.