I have an untested - and I mean untested - coin door with a Mars VFM2-L1 bill acceptor in it.
It's an over under style, one coin slot, one bill acceptor. I'll include the security lock pins and the plastic coin bucket. I think there is a meter attached to it also.
I couldn't test it because the unit it hooked into was broken (shorted or something). The power supply was torn out. I had another unit like it that worked all the way. I sold it on ebay.
It should take old bills, I'm sure it doesn't take new ones. I really have no clue as to how to connect it to a computer (if anybody knows, start a topic about it). I have no reason to believe it doesn't work, but I didn't test it.
It looks good, it's not rusty and I'll supply pictures if requested.
Make me an offer. It costs me $12.50 to ship it USPS.