check your local paper, and make sure you do some research on the breeder, there are so many yorkie puppy mills out there, it's ashame !!!!
and i hate to tell you, it's going to be very hard to find one under $1,000 from a good breeder- i live in PA too. and i have two of them, you can also go on the AKC web site to find some good breeders, that's what i did.