Sometimes the only thing you need you need to make a good mattress a great mattress is a topper. These Lucid 3-inch thick mattress toppers are made with memory foam gel and have an impressive 4.2-star rating nearly 4,000 reviews. The price on the queen size has been cut down by about $25 and the king is down over $30 in today’s Gold Box, but these prices will only last until the end of the day, so don’t sleep on it!