The IKEA mattress topper is perfect for Stanford on-campus apartments, which all have full-sized beds and bad mattresses. It made a huge difference in my sleeping experience! Even though it has been used for two quarters, it still looks like new and is very clean.

IKEA sells it for $99, and it's the most popular mattress topper there. Details on IKEA website: https://www.ikea.com/us/en/p/tananger-mattress-topper-white-70298243/