What is the cost of “free” trades?
"In the case of Wells Fargo, I believe that free trading is linked to your overall banking relationship with the firm. So if you have a checking account with a balance of $X, or  a total relationship with the bank (""relationship"" is usually defined as loan balances + deposit balances) over a certain amount, they give you a plum like free stock trades. The theory behind this approach is that banks want to be a one-stop shop for you. The idea is that they can market the banks products to you over a period of years (lowering customer acquisition cost) and offer you a level of convenience that allows them to charge a premium for services. For example, many people will pay a rate or fee premium on a mortgage or car loan so that they can do all of their business in one place. In other cases, free trading is linked to marketing campaigns by funds. Charles Schwab started this with the ""no transaction fee"" mutual fund store many years ago -- transaction fees are actually paid for by the mutual funds who pay for placement in the program. ""Free ETF trade"" programs are similar."
You'd need millions of dollars to trade the number of shares it would take to profit from these penny variations.  What you bring up here is the way high frequency firms front-run trades and profit on these pennies. Say you have a trade commission of $5.  Every time you buy you pay $5, every time you sell you pay $5.  So you need a gain in excess of $10, a 10% gain on $100.  Now if you wanted to trade on a penny movement from $100 to $100.01, you need to have bought 1,000 shares totaling $100,000 for the $0.01 price movement to cover your commission costs.  If you had $1,000,000 to put at risk, that $0.01 price movement would net you $90 after commission, $10,000,000 would have made you $990.  You need much larger gains at the retail level because commissions will equate to a significant percentage of the money you're investing. Very large trading entities have much different arrangements and costs with the exchanges.  They might not pay a fee on each transaction but something that more closely resembles a subscription fee, and costs something that more closely resembles a house. Now to your point, catching these price movements and profiting.  The way high frequency trading firms purportedly make money relates to having a very low latency network connection to a particular exchange.  Their very low latency/very fast network connection lets them see orders and transact orders before other parties.   Say some stock has an ask at $101 x 1,000 shares.  The next depth is $101.10.  You see a market buy order come in for 1,000 shares and place a buy order for 1,000 shares at $101 which hits the exchange first, then immediately place a sell order at $101.09, changing the ask from $101.00 to $101.09 and selling in to the market order for a gain of $0.09 per share. "Free, huh? From their Commission and Fee Schedule:  So if you literally bought two shares, then the SEC added one penny in fees and FINRA added one penny as a ""Trading Activity Fee"" Note that there are several other fees on their schedule that may not apply to you. If you had bought 100 shares instead, your total fees would have still been only 2 cents, but you would have lost $4 on the trade.  So the fees are minuscule when you start doing larger orders.   However, That should not discourage you from experimenting and learning.  I'd rather pay 2 cents in fees on a 4 cent loss than 2 cents in fees on a $400 loss.  Just chalk it up to the cost of experience." The commission is per trade, there is likely a different commission based on the type of security you're trading, stock, options, bonds, over the internet, on the phone, etc.  It's not likely that they charge an account maintenance fee, but without knowing what kind of account you have it's hard to say. What you may be referring to is a fund expense ratio.  Most (all...) mutual funds and exchange traded funds will charge some sort of expense costs to you, this is usually expressed as a percent of your holdings.  An index fund like Vanguard's S&P 500 index, ticker VOO, has a small 0.05% expense ratio. Most brokers will have a set of funds that you can trade with no commission, though there will still be an expense fee charged by the fund. Read over the E*Trade fee schedule carefully. An additional way to get a better grip on the mechanics of what you're looking to do is to use a paper trading tool. For example, thinkorswim gives you $200k in virtual money to trade with- money you don't have to worry about as you might initially make mistakes in trading futures. As mentioned above, each product has it's own pricing and trading options on futures (derivatives of derivatives) is even more confusing, so you'll be well-served by a risk-free learning tool. Consider trying a broker that offers free trading. Robinhood is one such broker. a) Contracts are for future delivery of said underlying. So if you are trading CL (crude oil) futures and don't sell before delivery date, you will be contacted about where you want the oil to be delivered (a warehouse presumably). 1 contract is the equivalent of 1000 barrels. b) 600 contracts depends entirely on what you are trading and how you are trading. If you are trading ES (S&P 500 e-Mini), you can do the 600 contracts in less than a second. c) No fees does not make particular sense. It's entirely possible that you are not trading anything, it's just a fake platform so they can judge your performance. d) The catch typically is that when it's time to pay you, they will avoid you or worst case, disappear. e) Trading is a full-time job, especially for the first 4-5 years when you're only learning the basics. Remember, in futures trading you are trading against all the other professionals who do only this 24/7 for decades. If you are only risking your time with the reward being learning and possibly money, it seems like a good deal. There's typically a catch with these things - like you would have to pay for your data which is very expensive or withdrawing funds is possible only months later. "Emotion aside, you can calculate the cost of the funds you have tied up at the bank.  If I can earn 5% in a CD, my ""free"" checking with minimum $5000 balance really costs me $250/yr. You have money tied up, I understand, but where would you place it otherwise, and at what return?  The subject of frequent trading even at zero cost is worth addressing, but not the real subject of your question. So, I'll leave it for elsewhere." "I think to some extent you may be confusing the terms margin and leverage. From Investopedia Two concepts that are important to traders are margin and leverage. Margin is a loan extended by your broker that allows you to leverage the funds and securities in your account to enter larger trades. In order to use margin, you must open and be approved for a margin account. The loan is collateralized by the securities and cash in your margin account. The borrowed money doesn't come free, however; it has to be paid back with interest. If you are a day trader or scalper this may not be a concern; but if you are a swing trader, you can expect to pay between 5 and 10% interest on the borrowed money, or margin. Going hand-in-hand with margin is leverage; you use margin to create leverage. Leverage is the increased buying power that is available to margin account holders.  Essentially, leverage allows you to pay less than full price for a trade, giving you the ability to enter larger positions than would be possible with your account funds alone. Leverage is expressed as a ratio. A 2:1 leverage, for example, means that you would be able to hold a position that is twice the value of your trading account. If you had $25,000 in your trading account with 2:1 leverage, you would be able to purchase $50,000 worth of stock. Margin refers to essentially buying with borrowed money.  This must be paid back, with interest.  You also may have a ""margin call"" forcing you to liquidate assets if you go beyond your margin limits. Leverage can be achieved in a number of ways when investing, one of which is investing with a margin account."