You're right, there is a big difference in the price charged for a yorkie. But, I've learned a high price is not always indicative of quality bred. Even from an exhibitor/breeder you might be surprised at how much less they will charge for a yorkie versus the scammers trying to exploit the breed by selling teacups and "rare" yorkie colors.
Most puppymills do not register AKC, although there are some that will or advertise that they do and don't (it happened to me). So, "no" just because a breeder registers with AKC or AKA (?) it is no guarantee of the breeding facility or quality of the dog.
I would suggest you contact the YTCA's breeder referral page. And even then research your breeder, ask questions, attend a dog show to meet the breeders and see the dogs.
Yorkshire Terrier Club of America About The Club
If you're in Tacoma, WA I checked and there are several upcoming dog shows in your area, you might want to attend one of them.
InfoDog List of Pure Bred Dog Shows Held in WA