just putting the title "touch pro 2 sprint" or whatever, they will tell you the average selling price.
eBay! sales hub (what's it worth?)
for whta it is worth, in october last year (7 mos ago) i got 225 on ebay, but it ended up being to a half retarded 17 y/o female balckberry user (no offense to the infirm, the young, or the ladies, but you know thats a bad trifecta). she disputed against me a month later and i had to take a return. the paypal shit jacked up my bank account for a week or so. fortunatly it was a paypal only bank account that i was using, but it is at the same bank as my mortgage, checking, savings and credit line so you never know.
take the easy road and sell it locally or here for the 150 price range. make it a simple fast deal.