Macybed is a private label, house brand of mattresses made for and sold exclusively at Macy's. The Macybed brand includes foam and innerspring mattresses. They are made by major mattress manufacturers like Sealy, Serta and Simmons - depending on a model.
Unfortunately, major department store house brands do not disclose details about mattress construction, build and quality of mattress components, which tells us they want to compete solely with price, not with quality. Generally, they are made with lower quality materials but are often offered with a substantial discount.