yeah i thought about it, and then really thought about it, yeah it is cheap but it is unpractical to all hell you get no insulation so really hot in the summer and cold in the winter, 4 wheels as a foundation is not the strongest, you have no space to live and septic tank to empty often. and if you want to have a bit more space and have a decent insulation and accommodation, well a house was cheaper here.
so i guess that close to big cities it may make a bit more sense, but you really need to weight the good and bad of it.