The measure of an item's resale potential on the popular US-based auction website, eBay®.
Specifically, an item that has a high eBayability will be easily sold for a profit on the auction website.
A "long lightsaber" Luke Skywalker POTF action figure MOMC at a yard sale for $1.00 would have an extremely high eBayability.
Whereas at the same yard sale, a worn copy of "Madden NFL 06" for XBox for $15.00 would have an extremely low and quite possibly negative eBayability.
n.b. U.S. Dollars is not necessary to define an item's eBayability as Ebay operates in countries that use other currencies. It is however, necessary that an item be sellable on the website.