Which platform do you think is best?

I'm new to stocks, but i'm very interested in it and wish to begin trading in order to begin gaining experience. I would like to know on what platform I should use to trade. I head etrade a lot.. but i know theres potentially better ones out there. Give me the top 3 on your list and maybe why. I'd highly appreciate it. Thank you. Btw i'd like to begin trading with aboutt... 300 bucks? just to test the waters. thx