The Paws & Pals Steel-Framed Elevated Pet Bed ($25 and up), available in both medium ($25) and large ($30) sizes and is made with waterproof materials, so it's great for both indoor and outdoor use. It's also perfect for travel. The easy-to-assemble frame can be put together in as little as two minutes and takes up minimal space when disassembled. Plus, the fabric can be wiped down with cleanser or soap for superquick cleaning.
As well as being simple and durable, one Amazon reviewer mentioned, "The four protected/plastic 'feet' are also a nice finishing touch to not scratch any delicate floors."