Check e-bay for the going price. Also check their availability or scarcity.

http://search.ebay.com/search/search...prclo=&saprchi=

Pruchase Price + Listing Fee + End of Auction Fee + PayPal transaction fee + actual shipping costs...

Then factor in if some chump has one out there for some ridiculously low price that keeps people from looking at yours...

If you can make a decent buck after all that, then go for 2, sell one. That way the cost of the one you keep goes down.