I did a bit of a silly thing recently, and used the Flea Market to stud out about 4o of my wolves. (I intended to breed them all, save like three, but ADHD brain took hold and I left the project unfinished.)
Most of the wolves I used were under 1k, which seems great for a newer user, however, I disagree. I think the lowest possible price people should be posting Wolves for stud is 2k pebbles. Any lower, and the person who is studding the wolves out is missing out.
Logically, each breeding results in at least two pups. Unleveled, those pups can be released for 1k pebbles each. This means a breeding should be at least 2k for the studding person to break even for use of their wolf. Obviously, there is no upper end as to what you can place your fee at.
Just some thoughts after my wild puppeneing.