Stockpile lets you buy and sell stocks like most other stock trading apps, but it also allows you to gift single shares of stock or buy fractional shares with a very low cent trade fee. TD Ameritrade actually offers multiple mobile apps depending on your needs. Interest is earned on uninvested cash swept from the brokerage account to the program banks. Enter your trade into the app and presto, you own the stock without any commissions or trade fees. Popular Courses. See more. Buying and selling stock investments used to require a phone call to a stockbroker who would charge you an arm and a leg to execute your stock trade.