Are cheap memory foam mattresses from Amazon actually any good?

The consensus across the reviewers we read is that budget foam mattresses can sleep well for the price but rarely match pricier beds on durability and edge support. High-trust testers like naplab and Sleep Foundation found models such as the Zinus Green Tea and Novilla Bliss competent for lighter and side sleepers, while r/Mattress threads repeatedly warn about all-foam beds softening or sagging within a couple of years. Budget foam is best viewed as good short-to-medium-term value rather than a buy-it-for-life purchase.