Tired of a game and want to sell it?

Suppose you buy a game and you get sick of it. You're thinking, "Hey maybe I'll sell it to my mate across the road". Guess what,... you can't. It's not like a game you purchased for your PC or Mac and you sell it to one of your friends or on Ebay. The game is yours forever. Fortunately the paid for games/Apps are generally not too expensive so maybe it's not such a big deal but one of the problems I see is that if the App you buy is not what you expected or does not do what you expected then you can't get your money back.

Am I right or am I wrong?