we have a full size aerobed. Bought it from Kohl's online. My DS15 is the only one who has used it so far and loved it. Said it was very comfortable. We bought it only for when needed (guests take son's room, son takes aerobed.)
It has it's own pump and is ready to go very quickly. I didn't spend too much on sheets but they worked fine.
Look for sales though. The are somewhat expensive but Kohl's has them on sale quite often (also check linen's n things, etc.)