These clever people are using shipping containers, dumpsters and rubbish skips to create family pools at low cost. And you can take them with you if you move! Here are the pools they made --> theownerbuilderne.
Spa that is divided for double usage: one side swim spa with jets that come out to keep you swimming in place, and one side set up as a normal spa jacuzzi. Best of both worlds, relaxing and getting in a good workout!