There are sometimes adult dogs/bitches for sale due to people who could no longer keep their dogs because their cicumstances changed or are not fit for breeding purposes.  These dogs/bitches are sold as pets only and not for breeding purposes.  The fee for these dogs/bitches will normally only cover the spaying/neutering costs.  These dogs make wonderfull pets especially if you do not have the time to go through all the stages of raising a puppy yourself!