I think we'll use the futon for a mattress for now.
Though I'm hesitant to recommend them, I bought 3 new foam mattresses from The Foam Factory (
LINK). We've used them for one trip so far, and were pleased with them. We did a double with memory foam and 2 small twins for the bunks. The double fit perfectly, but the I had to cut the twins down to fit. I don't believe you'll find a better price anywhere else. Trust me...I scoured the internet.
I'm hesitant to recommend them only because of their customer service. Just place an online order and don't call them. It won't help. Regardless of my efforts to expedite the order, which their website says they will do, they refused to help in any manner. I called their office on multiple occasions to try and prod them along and express urgency, talked to 3 different people, and they all were about as useless as you know what. The person I talked with the most was named Jonathan, and he said "NO" to everything I requested and didn't offer to help on little bit. #1 rule in customer service: NEVER SAY NO TO THE CUSTOMER. If you want quality foam mattresses at a very affordable price, call them. If you want fast shipping and good customer service, call someone else.
Sorry about the rant.
