Follow me for wargames!
Refer to OOP reseller sites like nobleknight.com and trollandtoad.com, but discount 15 - 30% off their prices to get an idea what you may get in resale to another seller. Also check eBay.
It depends on the product and the price. 15-30% off the CHEAPER of the two sites may be appropriate, as each overvalues some games, and Troll & Toad is notorious for excessively high prices for OOP games.