Online trading fees vary depending on the broker, but most charge a flat fee per trade, typically ranging from $0 to $10. Fidelity, for example, charges $0 per trade for online U.S. stocks and ETFs [1], while Merrill Edge charges $2.95 per trade for online U.S. stocks and ETFs [2]. Additionally, certain brokers also charge a margin rate on the net balance borrowed. For example, if you buy $2,000 worth of Apple (AAPL) stock with $1,000 in margin and borrow $600, your online broker will charge an interest rate of 6% [1]. Lastly, Fidelity also charges a commission of $8.50 per trade for U.S. equity trades, ETFs, and options in a Fidelity retail account only [3]. References: [1] Common Online Broker Features & Fees - StockBrokers.com [2] 11 Best Online Brokers for Stock Trading of February 2023 [3] Trading Commissions and Margin Rates - Fidelity Investments