To me it doesn't really make sense to compromise on health just to save a few euros (if I understand what you are asking). Don't get me wrong, there are times when getting a cat with known health problems is a noble thing, like from a shelter or whatnot, to give the cat a chance and provide him a home, but when you are dealing with breeders, and getting a pedigreed cat, and still paying a lot of money, no, to me the one thing I'd look at above all else would be health. If you still want to give such a cat a change, maybe counter offer that you would like to take the cat off their hands and give him a good home for free