Walmart offers the GranRest 8" 3-in-1 Gel Memory Foam Mattress & Sofa Bed in Dark Blue for $102.68 with free shipping. That's $37 under our mention from two weeks ago and the lowest price we've seen. (It's the best deal now by $77.) It has a removable cover and can be used as a mattress, sofa, or floor mat.
Teaching can be tough, but the life of a K-12 educator depends a lot on where you live.