[um???]

That's... rather kind of you to offer, but I don't know what I could possibly offer you in exchange for such generosity...

[Also he does have a living space he managed to rent out above his newly acquired workshop, but he doesn't mention that just yet. He's curious to know what the other man is after by offering such a thing, because surely there must be a very large demand that Kaveh plans on making in exchange for something like this, right?]