Craigslist. Good used board racks are a thing of the past. Why sell your board for 50% of retail when you can get full price by doing it yourself.
I know Heritage in OC has some new Bing Pucks, and a bunch of used boards. Check out Greenlight in Manasquan. I've never been but I hear they have a bunch of used boards and lots of cool local shapes. I've been trying to get over there one of these days.
Brave New World In Point has a decent used board rack but a little over priced like everything else there.
second this... oc heritage has a ton of used boards right now, including a bing puck (not sure of the size)
Heritage has a good selection. Brave New World has a good selection too, but as others said, a bit pricey.
unless OP wants the board i'd be interested in that, could you post the size and price if you happen to see it again? (i have a bit of a drive to OC so i wouldn't do it unless he's not in the area)
Eastern Lines in Belmar usually has a good selection of used boards, they should be open by mid April
was in there today grabbing some wax for my new sled. it's 5'8" & $450, full color. sick little board if it's in your size range.
ah i'm 5'11 and 150 that's a bit too big. otherwise i'd be all over it. thanks for letting me know though