What is a used PR System One Auto worth?

I'm trying to get my DME to swap out my very lightly used PR System One Auto (and humidifier) with an S9 (the PR just doesn't provide enough humidity for my needs), but I'm not sure that they will do it. They don't even have the S9s in stock right now, which makes matters even more complicated. If I have to sell this, what do you think is a reasonable price to expect to get? It's got maybe 50 hours on it, is about a month old, has all the manuals and the case, and is in mint condition. Is the auction site here the best place to try to sell this? Thanks.

BD
check my PM to you. You might want to try your local Craiglist or CPAPauction.com

Here's another option:

http://www.secondwindcpap.com/Used_CPAP.html

They sell and also buy used xpap's.

If you want to see some past CPAPAuction sales results for the System One Auto, go here: http://www.cpapauction.com/searchListin ... &sitenum=0. Then click on the "Auction Status" drop-down box, choose "Closed Auctions", and click on "Update". Sold prices have varied quite a bit, but this may give you a rough idea of its worth. Be sure to factor in the fact that the machine has been used when pricing.