09 imac 21.5 resell value?

so i was thinking about selling my 09 imac but im not sure what it is worth can someone help me out with this i got it in early 2010 it had the 2.66ghz core 2 duo and 4gb of ram its in mint condition

Mac2Sell - Guide to used Mac, iPad, iPhone & iPod - Evaluation - Argus Mac, iPod, iPad, iPhone Occasion should help you get a ballpark estimate.