It's worth bearing in mind that buying a 'healthy happy' puppy of any breed starts with choosing the best of breeders.
A good breeder will have done all the necessary health checks on the parents, and probably several generations back too. The stud dog will be known to the breeder as a good match both physically and mentally. The breeder will be able to give you chapter and verse about what they have or are hoping to produce with this litter, they'll explain why the stud was chosen, the history of the bitch and, will probably have a detailed archive of photographs and show results to demonstrate their success. If they are reasonably new to breeding then they'll also have a mentor that will have much of this background information.
I appreciate that not all breeders are like this but you'll need to aim high, particularly with the breed you are looking for as this is a popular choice of backyard breeders I think. Contrast the best of breeders with the type of person that is breeding for profit and you'll see why good choices now mean that not only will you get the happy healthy pup you are looking for BUT one with the best chance of growing into a healthy adult dog. The right breeder will give you and your dog a lifetime of backup and support :)
Good luck