If you buy the PS3 version of Sony Online Entertainment’s action MMO DC Universe Online, you had better stow any plans to trade it in after you are done playing. According to a report on Lazy Gamer, the PSN code that comes packed with the retail game is a one-time use code, which means the person who uses it first is the only one that can use it with that particular disc.
From an SOE representative:
"Once the PSN key has been consumed with a disk it cannot be resold/replayed with the second user adding a sub – only the original consumer can use that acct."
SOE also said that the retail disc and the PSN code are one and the same, meaning it is completely worthless after that first use. Further, there is no way (currently) that a second hand user can obtain a new code.
If you see the game for sale "used" at GameStop, avoid it like the plague because it is useless. Super. Hero. Coaster.
Source: Lazy Gamer