15 a pop? man! Order bulk, save loads :-) You can order quantities that work for you and still save a ton of loot by ordering even as little as 40 rats at a time (my typical order now is 400 every 3 months). . .
My wife would go off the deep end if I tried to put 40 rats in my freezer I only have one snake so I just pick up one from Pet* on the way home from work every Friday. There is a small pet store that sells them from some local breeder but it's way the hell out of my way. For now I just suck it up. It would probably cost me that much in gas to drive across town!