How much does a Pit Bull cost?

Long-winded, but the answer to this question is slightly complex. The cost of a puppy would ideally be a direct reflection on the work put into the parents. Therefore, puppies from different sources are going to cost different prices.
A puppy from a backyard breeder who has done nothing but breed two pets together should be relatively cheap, probably $50-200. Generally, this money just goes back into the breeder's pocket, minus the cost of raising the litter.
A dog from a rescue group or animal shelter will cost around the same price as above. The adoption fee covers the cost of getting the dog spayed/neutered; up-to-date on shots and wormings; and probably including a collar, leash, crate, etc.
A puppy from a reputable breeder will cost probably $500-1200. It can depend on whether or not the pup is considered show-quality. It will also be dependent upon the amount of money that went into showing the parents to their championships, earning various working titles, and paying for the genetic health testing. As such, breeders who only do one or two things should not charge as much as a breeder with proven top-quality dogs.

I personally would not pay more for an APBT than that. There are some breeders charging an exorbitant amount of money for their pups, anywhere from $2000 and up. These breeders generally make a living off their puppies, and are not putting in the legwork that a reputable breeder would do. They cater primarily to amateurs who believe they are getting something unique by paying an obscene amount of money.