I originally built a bankroll through freerolls. It took ages, and right when I was moving up to stakes where I could make
real money the government shutdown Stars, Full Tilt, and Absolute, which set me back.
If I was starting out, now, I would just make a deposit. Put $50 or $100 online and then play the micros and build it up from there. Actually, I did take my own advice when I moved to ACR. I just went ahead and made a deposit, instead of grinding their freerolls.
It's not that you can't play them, but boot-strapping yourself from freerolls is not an easy task.