Something that I've run into before is the fact that dogs who are for sale for bones-only aren't found in the Life > Search. Unless you come across one while searching through a kennel, seeing an advertisement or finding one for sale for $$ and bones.. you won't be able to find one.
I always thought this was a bit strange but I personally have worked around this by putting the $$ amount to an insanely high amount and putting the bone amount to a normal amount. [This would probably explain why many users see dogs for sale for high amounts]

My suggestion is to make it so that dogs for sale for bones can be searchable.