Overstock has this 1" Memory Foam Mattress Topper for only $36.79 after this 8% off coupon (there is also a 10% off coupon for new customers). The memory foam is a gel-like substance that adjusts to the warmth and shape of your body, making your bed more comfortable. The 1" size is the most affordable (everything from 1" to 4" is available). 166 Overstock users have rated it 4.5 of 5. Shipping is $2.95 and there is no sales tax (except UT, IN).