Craig's list and google for the camera's. Yes the film still is sold. Don't know about costco but if you call around you will find it. Camera shops will point you in the right direction, so will google. Good luck. My sister has done quite a bit of this,too  and so has my nephew and his girlfriend (shes a model) they all love the technique.

PS garage sales are really great for the cameras usually 2 to 6 dollars.....a steal!