Try this sleepover mattress idea - an alternative to an air mattress
Scroll down page to end of article listings.

Having some sort of mattress available, no matter how simple, is helpful when your kids are having friends sleep over. It's not always practical to own and store a standard spare mattress just in case of a sleepover. Find out here how to quickly and easily make or buy a pillow mattress, which is a convenient foldaway alternative to an air mattress - and it can't leak air!
Read more