You can buy a mattress from several places depending on your preferences for type, price, and shopping experience:

• IKEA offers a wide range of mattresses including memory foam and pocket sprung options, with sizes and firmness levels to choose from. They provide a 365-day return policy and home delivery or store pickup options

• Beliani.nl has mattresses with discounts up to 70%, featuring different types and firmness levels, including 7-zone designs

• Online mattress retailers like MattressOnline.co.uk provide a large selection of mattresses with next-day delivery and various styles including pocket sprung, latex, and memory foam. They carry well-known brands and offer both budget and luxury options

• Walmart.com sells mattresses in various sizes and types, including memory foam and hybrid mattresses, with options for free shipping or store pickup

• Mattress Firm is a popular retailer with top brands such as Tempur-Pedic, Purple, Serta, and Beautyrest. They offer free and fast delivery, financing, a 120-night sleep trial, and frequent sales

• For Dutch shoppers, brands like Emma and Matt are available online, with options for delivery in a box and trial periods. Physical stores such as BeterBed, Beddenreus, and Jysk also sell mattresses, often located near home improvement stores like Gamma or Praxis

In summary, you can buy a mattress at large furniture and mattress retailers like IKEA, Beliani, Mattress Firm, or Walmart, either online or in-store. Online mattress companies also offer convenient delivery and trial periods. For the Netherlands specifically, stores like Jysk, Emma, and local mattress shops are good options