Well, there is two different sides there with endusers and reseller prices.
Endusers are pretty much impossible to predict, as I have seen some really poor quality domains fetch in the $XX,XXX price range where I would not have paid $20 for them!
As for reseller prices, I would low $XX. Probably under $40 each...
In auction, you will get a value somewhere around what 2 of the above posters mentioned - high $X to $1X. You could try selling them here in the auction forum or on eBay -- eBay is rather unpredictable but sometimes leads to higher sales results than you would see from a reseller.