I've tried selling some stuff to Knight Torres, and she appears to take the stuff without giving any caps. My caps count does not go up, hers does not go down. Also, both Knight Torres and the Great Khans armorer seem to have a lot of issues with weapons "cloning"; for example, I open their inventory, see two half-broken Thermic Lances and buy them. When I open their inventory again right after that- WITHOUT reloading- I find the same two Thermic Lances in the same condition for sale again.