There is a basement apartment for sale on AOL. It's in London. 73 sq feet. 350K.
73 square feet? That's the size of a bathroom.
It's outrageous - worse than Manhattan - because you can't build up, it's not a high rise district. No old lofts or anything like that to convert, all built over long ago.
Whoever might be in the market for something like this would be better off to move a little farther out of town, or rent.