As others mentioned, prices range anywhere from $1500 to $2500 and your best bet to buy a healthy Yorkie is to research a reputable show breeder. When they breed for show dogs, not every litter produces all show quality puppies. They usually select 1 or 2 show potentials and then the rest of the puppies could be sold at pets. This is the BEST way to have the most assurance that your puppy is healthy. To find reputable breeders, you can try to contact the ones listed in the AKC listing or you could also visit the next dog show in your city and meet them in person (which is what I did). That way you can ask questions and learn more about how they breed and about the breed. If you meet them at a dog show, you're eliminating the risk of running into those online breeders that call themselves "designer breeders" who are only after your money (known to sell teacup puppies for over $3000).
Any of the classified-type of websites that try to sell you puppies for under $500 is very likely from a puppy mill or a backyard breeder. There have been so many stories of sick puppies, so be very careful on the breeder you decide on. Remember that any person who puts two dogs together and breeds them will call themselves a "breeder". Some may claim to have bred for years, but they may have very poor breeding practices (like inbreeding) just to pump out enough puppies to make a living. It doesn't mean they know anything about their health history! I can't say that enough times! So you need to ask lots of questions.
OR...I would also highly recommend adopting a Yorkie that is 1 year and older from a shelter that has been tested to be healthy. Or at the very least, they'll have some kind of record on what issues the dog may have and you can then determine whether or not it's acceptable to you. So many people buy Yorkies and then later realize how much work they are and abandon them. It's very very sad.
