If you need a cheap alternative... Try picking up one of those memory foam mattress toppers, and put it directly onto the floor. I have been using it for about a year now and its been WAY better than a bed has been to me. I used to just layer blankets on the floor as my bed, but that was still way too firm. The memory foam topper directly on the floor is the perfect combination of firmness and softness. It allows me to rotate to a comfortable position all night as need be.