
& of course there is fashion the more popular the breed often the higher the price(you can just about name your price when selling cavaliers & just because you pay a lot doesn't mean quality) & then novelty new breeds or designer crossbreeds & finally there is snobbery being able to brag about paying £x,000 for a dog !
A KC BC for example is around £400+ but an ISDS BC may only be £200 or less & an unregistered BC £50
There is a puppy dealer near here who sells his dogs from £400 & they are basically puppy mill/farm puppies bred for money & both health & quality is poor