I don't know about that costco, but I've got 5 within an hour's drive (they finally opened one 5 minutes away) and even though it's two states, the prices are consistent between all locations. I mainly hit the Virginia locations for the booze, we can't get it at the Maryland Costcos.
They've started to incorporate INSTANT rebates on the film-I always would forget to send all the stuff in. My husband picked up our film for our trip next week, and a 6 pack of advantix 200 was around 11 dollars and a package of 35mm 200 speed was around 7 bucks!
Also got a good deal on water and gatorade recently!
Suzanne