Found CNC Part, what should I offer?

[ZipSnipe]

Hey I was at a metal surplus shop here in town and I happened across part of a CNC linear slide, it had about a 20 "x3"x 1 1/2"long steel frame with a long screw and guides(nice smooth action), with big 1/2 aluminum mounting brackets, it looked like it was part of a z axis(that is the vertical part of cnc right?) kinda like it would hold the cutting device. Any way my question is the guy wants me to make him an offer for it($20 offer failed) so what would any of you think a good offer could be?

[ViperTX]

....hmmmmm....try $30....but it's a wild ass guess with a picture or more information like Part Numbers, etc.

[ZipSnipe]

Yeah I know I wish I had a camera, I seen a part similar that was selling for about $185. This surplus place( I wish I owned it) they have got all kind of stuff, lots of steel and aluminum. An example of pricing, I went to Home Depot to price out all the aluminum I needed to make a small 18" brake came to $45(you can get one from Grizzly for about half that) got to this surplus place and walked out with all the metal I needed for $6......