I bought a air mattress a couple of months ago I never even opened the box but I lost my receipt. I was wondering if I could bring in back and get a bigger mattress and pay the difference

Yes walmart will return anything as long u have an id and u will get store crediit

Yeah, you can take it back and exchange for another one or they will give you a gift card for the amount.

depends on the condition of the air mattress

Yes

Yes as long as it hasn't been over 90 days

Yes you can they will work with you.......