how do you think, what is the best strategy to play freerolls
I think there are quite a few threads with questions more or less like this one about
freerolls. It's really a matter of choice. I gave up freerolls a long time ago, not because i didn't like them, but because of the time i use to invest. 2k->10k player freerolls are very hard to cash in, and assuming you survive, you will most likely devote a few good hours, with potentially the same result over and over again, like being busted before you're ITM.
Don't know about
888, since i can't play in my country, but
pokerstars has SNG's starting at 0.10$ (forget the 0.02$ it's worse than a freeroll). With a 10$ min deposit (not looking to advertise) you can play 100 of those, time better invested, than in freerolls which you have way lower chances to actually make a profit. Restricted freerolls however, like the ones provided by CardsChat, are a different story. Not every hillbilly with $$ signs in their eyes get in, and if you play it cool, there are very big chances to hit the money.
As per strategy, if you're bent on playing freerolls anyway, i would recommend being tight early in the tournament until hasty people and allin-ers "pass out", and then try to build your way up. Good luck.