A very nice AR w/ premium optics & 1000 rounds = $4000 high average price.
Simpsons pinball party = $6,500 low avg price
I think most people offer these kind of trades hoping the seller doesn't know any better. A cheap AR without optics and 1K in ammo can run you under $1,500.
Can't think of any wierd offers for my games, then again I don't sell them very often.