I'm assuming here, but if you're posting this question then either you're already feeling guilty about the possibility of selling it or you are worried about what your friend and the guild think about it. I'd say if you can get $600 for the quilt, then donating some of the proceeds back to the guild for them to use to purchase materials to make for their next quilt to raffle would help to smooth the ruffled feathers. While I do agree it's yours to do what you wish, if it was me, I would feel very guilty about making that kind of profit off of something that was for a fundraiser. Around where I live even if you would win a 50-50 raffle at a fundraiser, the winner typically pockets half of their winnings and donates the other half back to the cause. Good luck making your decision.