Appropriate model for deferred costs as a line-of-credit
There's no standard formula. You can compare the going rates on the market for unsecured LOCs and take that as the starting anchor. Unsecured lines of credit run in the US at about 8-18%. Your risk should be reflected in the rate, and I see no reason why the rate would change throughout the loan. As to the amount of principal changing? Just chose one of the standard compounding options - daily (most precise, but most tedious to calculate), monthly average balance, etc.
"The question asked in your last paragraph (what's the downside) is answered simply; if you take out a loan and close the cards, that's a ding on your score because your leverage ratio on this portion of your credit jumps to 100% or more, and because you'll be reducing the average age of your lines of credit (one line of credit a few days old versus five lines of credit several years old each). If you take out the loan and don't close the accounts, it's one more line of credit, increasing your total credit, lowering your leverage, but making institutions more reluctant to give you any more credit until they see what you'll do with what you have. In either case, assuming you can get the loan at less than the average rate of the cards (that's actually not a guarantee; a lot of lenders will want APRs in the 20s or 30s even for a title loan or other collateralized loan), then your cost of capital will also go down. That gives you more of a gap of discretionary income that you can better use to ""snowball"" all this debt as you are planning. Another thing to keep in mind is that the minimum payment changes as the balance does. The minimum payment covers monthly interest at least, and therefore varies based on your interest rate (usually variable) and your balance (which will hopefully be decreasing). A constant payment over the current minimum, much like a more traditional amortization, would be preferable." With an appropriate selection within a 401K and if operating expenses are low, you get tax deferred savings and possibly a lower tax bracket for now.  The returns vary of course with market fluctuations but for almost 3 years it has been double digit growth on average.  Some health care sector funds were up over 40% last year.  YMMV.  With stocks and mutual funds that hold them, you also are in a sense betting that people want their corporations to grow and succeed.  Others do most of the work.   Real estate should be part of your savings strategy but understand that they are not kidding when they talk about location.  It can lose value. Tenants tend to have some problem part of the year such that some owners find it necessary to have a paid property manager to buffer from their complaints.  Other owners get hauled into court and sued as slum lords for allegedly not doing basics. Tenants can ruin your property as well.  There is maintenance, repair, replacement, insurance against injury not just property damage, and property taxes.  While some of it might be deductible, not all is.   You may want to consider that there are considerable ongoing costs and significant risks in time and money with real estate as an investment at a level that you do not incur with a 401K.  If you buy mainly to flip, then be aware that if there are unforeseen issues with the house or the market sours as it can, you could be stuck with an immovable drain on your income.  If you lose your job could you make payments?  Many, many people sadly lost their homes or investment properties that way in 2008-2010. The only ways to increase your after-tax income are to increase your tax-deferred savings (401k), increase your tax deductions, or increase your pre-tax income. Increasing tax-deferred savings is great for the long term, but will usually not result in a bigger paycheck (though net pay including the savings will go up). This is, however, probably your best bet for reducing current tax liability. Increasing deductions usually involves spending money--on charity, mortgage interest, other taxes, etc. So, while you may reduce your tax liability, you probably won't end up with more money in your pocket. Also, if you are single and aren't paying a mortgage, it probably won't be easy to exceed the Standard Deduction. Which pretty much leaves you with asking for a raise, getting a better paying job, or taking on a second job to increase your top-line income. The cost to the store is small. They may have to pay a slightly greater fee because the transaction is now bigger. They do need additional cash on hand. Even though the majority of transactions are electronic (credit/debit) or check, the local grocery store still seems to have significant cash on hand. This is seen as a customer service. If there is a 2% fee the $50 advance costs them $1 for the minority of customers that take advantage of it. After more than 10 years of doing this they have figured this into the cost of groceries. Of course the credit card company could also waive the fee to store. My credit card online statement does tell me how much cash back was received. The line says date, store, amount ($40.00 cash over and $123.45 purchases) $163.45 total. Therefore the credit card company knows that cash back was used. Standard Repayment can be quite burdensome. Fortunately, it looks like FedLoan Servicing offers a variety of payment plan options, and even provides a calculator that you can use to compare them given your adjusted gross income and current loan balances. This won't reduce that $420 to $0 but it may bring it down significantly.  I agree with @littleadv that you need legal advice to answer your other questions. That being said, I can tell you that it is possible to go into deferment and/or forbearance at any time (not only before you start making regular payments) as long as you meet the criteria.  Otherwise, it may be worth looking through other questions and answers on here about lowering expenses and increasing income. There is a lot of good advice for people in similar situations to yours. If you are truly in hardship, even with a full-time job, you may qualify for supplemental nutrition insurance, a.k.a. food stamps.  Best of luck. Maybe one of my issues is that I have a 5 year model with a terminal value. The repayment of debt principal is outside this time frame so I don't assume any repayment.   If you're valuing a company share price though you don't model all debt repayments. "Ugh... yes, you have to tell us what information you have available. It would be a completely different answer if, for example, you had a balance sheet for a prior period and an income statement for the current period and had to estimate the working capital accounts. If you can't be bothered to ""want to give the problem"" nobody is going to be bothered to help you with it.   Inventory days = days of COGS in inventory. (15 / 360 times cogs). AR is 35 days of sales in AR. 35/360* sales. Vendor credit is accounts payable -- 40 /360 * COGS.   If your sales and COGs are given by operating cycle rather than annually, use 50 instead of 360. (for whatever reason, convention says use 360 instead of 365)." Attempting to treat every BU as a profit center is doomed for failure.   Some of the record keeping for charge back models are good for data collection and any BU that primarily acts as a profit center can easily do charge backs with other BUs that utilize their services (say a publishing company asking the BU in charge of printing to provide some internal material). If the business function is not a core competency and is not a profit driver it is a cost center and should be treated as such.   For cost center based BUs record keeping, budgeting and controlling your commitments are key however you have a higher chance of being jerked around in some scenarios, this really comes down to the kinds of leadership around the BU.