Yorkie prices range from $500-$10,000 according to posters on this board
When I was researching I decided the most important thing to me was the breeder's reputation. I didn't know anyone with a Yorkie so I read all I could at
www.ytca.org and started contacting people on their breeder referral list. That wasn't very successful (no pups) but one of them gave me a contact which was my first chance to see a pup in person. That still didn't work out so I attended a Yorkshire Terrier show and met a couple of show breeders. I didn't want a show dog but I wanted the experienced breeder. Eventually I got a pet quality pup from a show breeder.
I would never buy from a pet store, newspaper ad or the internet. Some people have found wonderful healthy pets that way but I didn't want the risk.
Now that I have found this board and kind of "gotten to know" a few breeders here I would definitely buy from some of them. I would also take referrals from members here that got great pets.
good luck