Try United Yorkie Rescue, YTNR, SOSdogs or other small dog rescue sites. It is next to impossible to find a well bred, healthy pup at that price, but you may be able to give a good home to a small rescue dog that needs one for just a few hundred dollars. Also the site
www.buyingapuppy.com gives good info on finding a reputable breeder, if you decide to try that route. Stay away from pet store pups.