
In order to breed sound healthy dogs rather than trusting to luck reputable breeders will do various health screening tests. these are all very expensive. Also to breed the best posible puppies, in the USA a bitch may be shipped to the most suitable stud, who might be thousancs of miles away, or alternatively go therough the expensive process of artificial insemination.
If these breeders did not care about how the dogs compared to the breed standard you would soon find yourself unable to find a Bull Terrier that looked like it's breed, but one of the poorly bred specimins of amny breeds, where one is scratching ones head wondering what it is.
Not all likely health problems will be visible at time of purchase, and you could end up paying dearly for a cheap pup. You could also end up with one with an iffy temperament.
Going to a reputable breeder who knows his dogs and can possibly show you several generations, you have more chance of getting a similar pup in looks and caharacter.
In the UK most pedigree pups are likely to cost in this breed £600 to £800 ($900 to $1200). The bulk of the price reflects the money spent on rearing the litter and the cost of all the above. any profit helps defray the breeders expenses keeping their other dogs. A puppy farmer (miller in USA) does not keep any dogs that are of no commercial use to him. Most reputable breeders keep most of their dogs until their death, and only take a few litters from a bitch, so any profit made on her pups will not even touch the cost of her upkeep throughout a long life.