Lots of ways to buy an RV Mattress online. We bought one from mattress insider. Their customer service was the best. Got their top of the line memory foam mattress but it was too soft, donated it to a local charity and got their latex mattress. Much more firm. Lots of people talk about memory foam or adding a topper, but to me that just makes them too soft. I need firmness due to my aging back. My point, any reputable company will offer a sleep guarantee and money back so look for that in your search.