Just to state the obvious, it's worth what somebody is willing to pay for it.
Is it anything like the old drilling setups they used to have at Kmart (and other retail stores)?
Unfortunately it's all about timing when trying to sell stuff like that. It also helps if you are willing to piece it out, and whether or not you are willing to ship.
Back at the end of 2006 I was able to nab an entire Kmart setup - Rockwell (Delta) drill (15-080), X-Y jig, all bits (except 1 1/4"), Brunswick ball fitter, bevel sander and discs, metal ruler, letter stamper and some other stuff - from ebay for under $500. I put a "reminder" bid on it and completely forgot about until ebay notified me that I was the winner. I never thought I would win it, and wasn't really willing to go higher than $500-600 on it anyway.
Seller wasn't willing to ship the item and I guess I was the only one willing to drive to Lansing to pick it up.
A few months later I was able to snag a "pro-shop going out of business" auction for $200. Landed the pitch gauges, a couple of quarter scales, bevel knife, workout tools, router shield, various inserts and slugs, etc. Also was able to win an auction for a Kaufman scale for $300-350 shipped.
All during that time I had watched many auctions go for much higher amounts - including just the jig for $300+ and scales for $500 or more.
About 1 1/2 (maybe 2) years ago there was a guy auctioning off a newer drill press and Jayhawk professional jig for something like $1250. Problem was that due to the size of the drill press shipping was going to be $300+. Maybe it was more. For some reason $1800 total comes to mind, but I really don't remember. It was still a great deal, but I didn't have that much to spend at the time.
I guess I wasn't the only one, since he never sold it - never even got one bid. I was able to convince him to seperate and just sell me the jig. Now, maybe one day I'll get around to removing the x-y and installing it!