I'll qualify first by telling you I'm in sales and negotiating deals is a daily task.

I would start as low as possible with the person who has the slide. If they want to get rid of the slide you are doing them a favor. I'd ask them if you can just have it for the labor of removing it. In the end they might be pleased as punch they have someone they trust to do the work and glad to let it go just for the labor.

Prices are all over the map on ebay for all kinds of slides. Ranging from 4K for an out of of the box corkscrew slide to $200 bucks for a used slide.

Here is the URL for the ebay search "pool slide"

http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40

The previous poster had a good idea in comparing slides on ebay to the slide in question. Again I'd start low and see what the threshold is. Good luck...This is timely as I've been thinking of installing my own pool slide.