Studio apartments are way more common in the city and thus they are often more expensive. My sister bought one a few years ago and for the space she has in the place, which is not much, I feel like she got ripped off. Maybe people are not so keen on paying a lot for smaller space?
I live far out from the major city so studio apartments aren't in my area. I know of a few homes that people rent out their finished basements as studio apartments. I think that is a good idea if you can swing it.