
It costs exactly the same to properly rear a pet puppy as a show prospect.
The costs of the litter start long before they are born with the costs of health testing, showing or working the dog, conditioning the bitch and the costs of the travel to the stud, possibly ovulation tests and stud fee etc.
I would be very suspicious of any breeder that sold their puppies at different prices unless one was non standard completely, and even then it still cost the same to rear etc.
A well bred pup of my own breed is around £600 and I expect that Goldens may be similar, but with such a popular breed there may be more than the very little variation we get in price based on geography etc.
I would contact the breed clubs and ask them for a ballpark figure for a well bred puppy.
More importantly ensure the relevant health tests have been done on the parents, which off the top of my head at the very least would be hip Scoring (with total score below high teens), Elbow scoring (no more than 1 for each elbow, ideally 0) and eye tested within the 12 months before mating.