It’s not difficult to trade fee-free. In our analysis, we conducted comprehensive tests on 17 online brokers, all of whom offer “free” stock and ETF trades. By free, they mean that they don’t charge any cost per share to trade. Brokers do pass along some trade fees charged by regulatory bodies and exchanges, but they are almost always miniscule and measured by fractions of a cent per share. Brokers may charge fees for other products and services, such as trading options, mutual funds, robo-advising, or transferring your money in or out. Some brokers also charge for reviews, comparisons.