I downloaded Coinbase, made an account, and threw $100.00 at it. Gotta start somewhere.
Cryptocurrency.
I bought about $40 of Bitcoin a few years ago just to walk through the process and see what it was all about. It was worth $1,500 when I checked yesterday.
Aside from that, I have had great service from Charles Schwab and Robinhood (which offers fee-less trades).