Yorkies are an expensive breed to own, and I'm not even talking about purchasing the puppy! The upkeep is expensive, and this breed is not for everyone. But if you already have your heart set on a yorkie, make sure you research a lot! Just bc a breeder charges a large amount of money does not make the pup any better than a lower priced one. And that goes both ways, just bc a pup is priced lower does not necessarily make it a poorly bred one. Price is effected by many things, and actually the price is relative. There are bad breeders out there who breed "teacups" and "teaspoons" and charge $5000 and up. Absolutely ridiculous! Or they say a pup is "rare" (which in fact could be a genetic defect) and sell for more $$$.
If you truly want a good breeder, i suggest you start from the breeder referral list at
http://www.ytca.org
There is also an informative thread here you should read:
http://www.yorkietalk.com/forums/general-yorkshire-terrier-discussion/201720-how-much-yorkie-puppy.html
It is much better to get a healthy well bred pup from a reputable breeder that may cost more, than to get a cheaper poorly bred pup from a byb with health problems down the road. the poorly bred pup will cost you more in the long run. Good luck!