Robinhood - commission free but long line.
Not sure if they will allow you to move BTC so something to research before using it.
Robinhood:
1. Is only available to five states in the US: California, Massachusetts, Montana, Missouri and New Hampshire.
2. There are more than 1 million people in line to get access to the app.
So they are not the best option right now. They do allow you to withdraw your BTC however.