Brokers have now entered the 0 fee war. Robinhood started the trend then other established brokers reacted and now offer 0 fee trading. They will make money by selling your orders to high frequency traders. Execution of your orders will not be as good and they hope you will trade more often.

List of popular us stock brokers:

Fidelity
>0 fee trading.
One of the oldest and largest broker. FDIC/SIPC.

TastyWorks
>Super cheap options commission. SIPC, no FDIC.

Degiro (Cheap broker for Europeans)
>2nd cheapest platform for Europeans, they announced an increase of their commission fees. Very quick registration process. But beware if they go bankrupt you may lose your cash balance they are not insured like other brokers. It seems they have €20k protection.

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If you don't live in the USA but want to trade or invest in US stocks, check which of those brokers accept residents of your country. If none of them accept residents of your country, do extensive research to find a reputable broker and what would happen to your cash balance sitting in their account if they go bankrupt.