You will want to go through your new trailer very carefully, inside and out, before you pay for it and sign the papers. A dealer never looks at your trailer as carefully as you do. Remember, if there is no warranty, as I assume there isn't, then the assurances that folks give you up front before purchase are worth the paper they are not printed on.
At the very least I would make sure every appliance and every slide operates as intended. Cooktops, propane/electric water heater, water pump, refrigerator, awning, and each slide (if any) should be operated and checked for proper operation. Most folks would suggest you get on the roof and make sure it has been maintained with caulk and has no cracks.
Tires should be dated from less than five-six years ago or you should probably plan to spring for new tires all around.
Your focus should not be the nickel and dime items, but anything -- like a slide-out or fridge that does not work -- that could cost you hundreds of dollars for repair.
