WANTED! 8' Funboard ---> ? next USED board ($500 budget)

I am looking for a used board that would be a good next board coming from an 8' funboard. I am hoping to find the best USED board for my money with a budget of $500. Some boards that I hear are really popular are the Channel Island Biscuit board, or maybe something similar. I am 6'1" and weigh about 175lbs, and located in Northern California. Good brand names, or shapes you think would be good would be helpful. I am steering towards a fish, or something like the Rusty Piranah, or 7s Superfish. Thanks a lot!