The best thing to do when pricing used items is figure what you would want to pay for them, not what you think they are worth or that they cost "X" amount when new, but what you would think is a good deal for them, then add a few dollars for negotiation room.
Based on your opinion of condition, w/o rims maybe $50-75 each. I would list them as "6 for $400 o.b.o." and see what kind of interest you get.