What is a Leaf Aptus 65 back worth?

[Streetwise]

I'm thinking about selling my Aptus 65 (Mamiya mount) back. It's about 5 years old and would be sold as factory refurbished with a 90 day factory warranty. I was wondering what it might be worth as such. I also have a Sinar P2 camera with both a 55mm Digitar and 90mm lenses in Rollie shutters (that use the Rollei Controller S). Just putting out feelers at this point. Not sure if the back would be worth more if bundled, or if stuff was parted out.

Thanks

Dave