I also build my bankroll with freerolls. After I got my 16 $ from freerolls I started playing 0,02 990 sit&go on pokerstars. I played those till 40 $ when I started to grind 0,10 sit&go 360 man. After I got to 50 $ I started playing 0,25$ 90 - man sit&go. Now I still play 0,25$ 90 - man sit&go and taking shots at 0,55$ tournaments (they are not so many tho so i play them all).
I have 150$ BR at the moment and I plan to keep building until I have 200$+ so i can play 180 man 1$ sit&go and regular speed 1,1$ tournaments. Hope this will work! 😀😀😎😉