Freerolls are great like that because there is nothing to lose and everything to gain. I like to get a huge stack fast or double up and spend the rest of my evening doing something productive. You have the best hand preflop and If you win the hand you are in a position to do some serious bullying (once the first hour is up and the maniacs have been knocked out). Call everytime and if you go out then either play in a different freeroll or go to the pub or something