I use Marnid's and Borcha's inventory as my portable merchants: I drop items onto them for free or for whatever they can afford. It works for now because I have too much denars than I can spend anyway, and really they're a portable bank when I need them.
However, it might come in handy to throw away items when you're on the run and trying to reduce your encumbrance; though how much effect that would have I can't say.