Robinhood
I like Robinhood because of its user experience. It used to display confetti whenever I made a trade, but this feature has been removed.
Stock Lending
I receive $0.01 monthly from stock lending.
Robinhood Gold
I pay $5.00 per month for Robinhood Gold, which provides a 3% match on my IRA contributions and $1000 of interest-free margin. Purchasing 10 shares of SGOV yields about $3.71 per month before taxes, effectively reducing the actual monthly cost to less than $1.29.