They hold their value pretty well, they are always on ebay, going for $800 and up. FCAW only models are cheaper of course. Only the really beat up looking ones go at the lower prices.
But they are very rugged/reliable machines. New, from ramweldingsupply is a pretty good deal unless you get a substantial break at the local welding supply. Former rental units are always for sale, at way to high a price imo. F&M Mafco usually has used models for sale, as well as a bunch of other pipe/welding related stuff.
You say a couple of small jobs, so renting one might be a good option if you won't have any further use for it.
I looked at a lot of used ones before deciding they were priced high enough that I'd rather buy new, but I need very reliable equipment, breakdowns cost me a ton of money.
I did buy a LN-22 off ebay for $40 and it works perfectly, it just looks extreemly rough.

JTMcC.

There's one for sale here for a lot less than $800: http://www.craigslist.org/eby/tls/64866835.html