
Listen to the instinct that made you stop and come and ask here instead of just buying!
Good, reputable breeders want to talk to their puppy buyers - they will offer a lifetime back up service in advice and also to take the puppy back if anything awful happens that means you cannot keep him (Obviously they are not superhuman and cannot be there at the drop of a hat but they care about puppies produced, and want the best for them for their WHOLE lives).
When you see the price of a well bred puppy, its not much more (in some cases LESS) than what Dogs4us charge, but for that price you are getting a WHOLE lot more for your money.
Reputable breeders ensure from day 1 that your puppy has the very best chance it can have of having a happy life - those first 8 weeks or so are actually the MOST important in your pups life for learning about the world and how to cope within it. Puppies that are sold in pet stores miss out on teh lessons they NEED and even if you buy a pup at 8 weeks from a pet store, you have missed out on half the 'magic' slot for best learning.
Buy from a place like Dogs4us and you will be playing catch up for the rest of that dogs life trying to make up for what he missed out on!
Puppies sold by places like this will be from parents who are poor examples of their breed, who have not been health tested for the various conditions we know some pedigrees can get (and its not that pedigrees get more health problems, its that we KNOW what they are and can test for them!) and will not be KC registered either. Whilst you may not want to show, there is no good reason to be breeding non-registered and non-registerable pedigree dogs, there are only BAD reasons for doign this (cutting corners, breeding from animals that are in fact not pure bred, breeding from animals too young, too old, too often!).
This is an investment, think of it as a maybe 14 year investment - its really worth putting in a few months research, time and travel to find the right puppy from the right breeder!