Above ground pools are just that, pool that sits in a frame on top of the ground. An above ground pool consists of a heavy plastic liner surrounded by a metal or wooden support. They come in a variety of sizes and shapes (round, elliptical, or rectangular) and there are even "do it yourself" kits for the adventurous pool lover.
Above ground pools can be portable, coming down and storing away in the garage over the winter or even packing in the van with your other belongings when you move. If the liner springs a leak, there are any number of inexpensive products to play little Dutch Boy. Relatively cheap, you don't even have to pay taxes as an above ground pool is not seen as a property improvement.