When I first got into poker, I was quite a lot in your spot- not wanting to use bankroll, wanting to freeroll as practice, not positive about sng or cash game.
Heres a bit of advice, if what happens to you is anything like what happened to me then it'll be a bit of help for ya:
-If you already have a preference in sng/mtt's, stay there. I knew I liked sng's/mtt's better, but because of soooo many people on 2+2 prefering cash game, I wanted to try it, and even though I did make some money there, I feel like I just wasted time because now I'm a SNG/MTT player strictly.
-Don't waste time on freerolls. It sounds like your doing much smaller ones than I was, which is probably better, but if I were you, I'd play the .25c no rake SNG's on Stars. They are good practice and you can work on the basis there and see what works. If you play with a TAG style there it is very easy to sit back and cash for the most part.
I'm not very far ahead of you in my poker .."career" I guess, but I hope that this will help ya out a bit.
You look to have a good start and I wish you luck