When people called me up to enquire about bella's pups, if the first question they asked was how much the pups would cost I simply told them to look else where as I would not sell a working cocker pup to someone who hadn't done any homework on the breed and was concerned about price above all else. In my opinion they should have been grilling me on blood lines, health tests, temprement and achievements of both sire and dam and the reasons for why the litter was being bred... price would be the last question to ask once you're satisfied that the litter ticks all of your boxes and you like the sound of the breeder and environment the pups are or will be being raised in etc...
My pups cost £470 (dogs and bitches) and that's for all of the KC registration, first set of vaccinations, worming every 2 weeks, two vet check ups, de fleaing treatments at 7 weeks old and one to go with the pup to its new home, docking and dew clawing with certificate, countless hours of socialisation, cleaning up after them, toys to go with them to their new homes, food, and all my pups went to their new homes almost completely house trained at 8 weeks old and sleeping through the night and also being used to spending time on their own away from their dam and siblings. Then there's the prenatal care for the bitch and stud fee, health tests and the year/s of research to find the right stud and to see in the flesh as many of the dogs in the pedigree as possible. I was lucky as no complications arose with the pregnancy and birth and all the pups were born fit and healthy and have stayed that way. Breeding is not for the faint hearted and is a very time consuming and expensive process. (I raised my litter in London)
Be very careful when you buy a pup on the cheap, as I can garantee you that a reputable breeder will know what their pups are worth and should have done all of the above. They will also be vetting you thoroughly when you ring up to gauge whether they'll let you have one of their pups. They should also be happy for you to come and see the pups but should ask you to wash your hands and take off your shoes before you see the litter to ensure cleanliness, if they don't do this then you should question how experienced they are and also how much they care about the welfare of the litter.
Buying a pup is not a particularly easy experience if you go about it the right way, you may have to wait a while for the right pup to come along and breeders will be protective of their pups but with a reputable breeder you'll get your moneys worth and a lot of support, whereas with a puppy farmed pup you will have problems and no support from the word go (IMO).
Good luck with your search for a pup
Try and go through the kennel club website or the breed clubs rather than free ads.
Best wishes
Mary