That's a lot of money for any puppy, more than I'd expect to pay for even a highly promising show, sport, or working prospect from an established purebred breeder who has excellent lines, breeding stock with show and/or working titles, and extensive health testing, including genetic screening and x-rays when necessary. So I have a few questions for you to consider.
What health testing do the parents have? I'm not talking "the vet says they're healthy", I mean have they been screened for genetic indicators of diseases/conditions that are common in bully breeds, have their hips and/or elbows been x-rayed to evaluate whether they'll potentially be producing puppies with dysplasia, have their knees been evaluated for luxating patella, have their eyes and heart been screened? And importantly - do the results of all these tests indicate that the parents are excellent specimens with a very low risk of passing on any genetic illnesses or harmful traits to their puppies? Are both parents (especially mom) at least two years old? Have either of them been awarded certifications or titles in any kind of sport or work to support the idea that they have excellent physical soundness or temperaments that would go towards producing puppies who also have sound bodies and wonderful, stable temperaments?
What are the breeders doing with the puppies each and every day? Have they been introduced to various sights, sounds, and experiences in positive ways? Have they been interacting with humans from day one, living in a family home, learning that things like the dishwasher, vacuum, TV, people working out, etc. are normal and not scary? Are they being offered different surfaces to walk on, toys of different shapes and textures that make different sounds? Have they been taking trips in cars, meeting a variety of kids and adults? Have they been working on separating the puppies slowly and carefully so they're less distressed when they leave their litter behind entirely for a new home? Even getting a head start on potty training and training in general? All of this goes towards helping puppies grow into confident, happy dogs, gives you a big head start on helping the puppy settle into your home, and helps prevent some of the most common behavior issues dogs face.
For $5000, I'd expect the breeder to be able to explain in detail all the health testing their breeding dogs have, all the ways they can show that the parents have exceptional physical/working abilities and/or wonderful temperaments that complement each other, and also have a comprehensive and intensive puppy raising plan to give them the best possible start in life. That's the value you're getting from a reputable, responsible, and ethical breeder, not the coat color (it's very rare for responsible, ethical breeders to charge more for certain coat colors) or even the breed itself. If they can't give you most or any of this, it's highway robbery.