I am seriously thinking of investing in one. I found one at Walmart that would be ideal for me and its about 130-140. Not sure if I want to spend that kind of money, but on the other hand I know I need to have something to exercise on. Since I don't have a sitter or a spouse, I am limited as to where I can go with my 3 year old. I won't even mention how wild he is in public. So it comes down to walking in my living room or a stationary bike. I am worth it. I can ride it while I watch tv. Its a recumbent bike, so it would not put much stress on my knee as the upright bike.
Here is a link to the bike, let me know what ya think!