I have attended/vended at 2 repticon events. Everything is the same on both days. Awesome events though, very well organized, great door prizes and raffles, friendly helpful staff.
I'm not sure what products you are referring to, but for the most part you are going to pay almost the same price as online, minus the shipping. For example, LLL seems to have the same prices at the shows as online (maybe a few exceptions) but you don't have to pay the shipping and it is in your hands right now! Frozen feeders are a great deal at the shows, I recommend stocking up as much as you need and/or can afford!