But if you are willing to do your own butchering you can get them for free.
People keep hens for eggs. When they stop laying they can either butcher them or keep them around as useless eaters who bother the other birds. A good portion of people do not want to do either so they give the live birds away.
You can generally find them on Craig's List.
There are a number of videos on YouTube that will show you how to correctly butcher and clean a chicken.
Actually, I was commenting on how cheap they were. A three pound Empire chicken cost me $15. It turned out to have no flavor unlike the old days when they had the most flavor. There has got to be some new koshering process that gets rid of any brining or salt residue that turned the joints of a bird into caramelized candy.
This old bird cost me 6 bucks for the same weight.