It's very difficult to give relevant advice here, mainly because we dont know what type of games you like. Do you like cash games, limit holdem, sng's? If the $50 is likely to be your main deposit for the forseeble future then read up on the bankroll management threads, there's plenty of them.
If you plan on cash games I know Stars do 1/2c games so you could start there and work your way up.
I built my roll up on Stars on the sng's, I wouldn't advise against building a roll this way, but the variance seems to be much higher. However if you use sensible BRM you should be fine.
Remember, building a BR takes time and a lot of effort. For the majority of us it's a grind. You need to be patient. Yes some can make really rapid advances, this usually involves running extremely hot and some major risk with your BR. But take your time and read up on a lot of strategy stuff, GL.