Lol, everything you mention, plus more than you can imagine. They'll cheerfully take your money any way you'll hand it to them; don't bring the children lest you be tempted to swap them for something. Wear comfortable shoes. Look around a lot before buying; you might find it cheaper next aisle over, or something you like better in the corner. Be prepared for severe shinyitus. Have fun
EDIT: a few more tricks for buying at trade shows. There will be ATMs and/or a change booth where you can cash checks for a fee, just in case you want to buy from a vendor whose credit card machine is broken. They all have them; nobody wants to slow down the money. The best buys are usually not the latest and greatest. Look for a vendor stuck with several of the previous model. He needs to turn his inventory capital so he can restock with newer gear and you can often buy near his cost. If you can get several buddies together who each want something, buying all of it together at a single vendor can yield nice discounts. Do not be distracted by Shiny Objects! Put on your tinfoil hat to deflect the sales pitches--trade shows usually feature better salesmen than Trump-- and look around. And don't miss the freebies: hot dogs, refrigerator magnets, samples of this and that, key chains, baseball caps; free stuff and loss leaders are everywhere, so load up. What you don't want you can give away.