As far as Stan knows, anything is possible. Or perhaps hardly anything is. Transdimensional Stan might know more about the supernatural than he lets on, but he’s still probably not going to have a wealth of information on demons and their powers to make use of. So maybe he tries, but he has no clue if any hypothetical trade offers are fair or not. For all he knows, this Alcor guy could be gouging him. If he learned anything from the Stan of the other dimension himself, he could be.
That said, Alcor might very well chose the path of denial rather than deals. It’s entertaining if nothing else. That, and he’s been this route before, with his Grunkle Stan, and it hurts to remember or realize that soon he’ll be gone from this dimension and he’ll lose them all over again.