Dogs (small and large) are 5,000 G's. The small dogs will let your sheep and alpacas in and out of the barn. Large dogs will do the same for your cows and Cats will help you with your chickens. One pet per farm animal. You can buy food for them at the general stores in either town. The more the friendship the better job they do, when you first buy them they may not always let your animal in and out. You can buy toys for them that will help with friendship at the general stores in both towns.