How does Gamestop get their retro stock? They would have to offer a fair deal on trade in prices and not, "I'll give you $5 for that Symphony of the Night game because it's a PSone game". They would have to rely on the customers who don't take the time to check what they have and assume that a Chrono Trigger cart has the same value as a sports game. So basically, they can either have cheap, unwanted games for sale or desirable but highly marked up games. Either way, it's a vast difference from 10 years ago when asking I asked a gaming store if they'll buy my boxed Pokemon Red game and they said, "no, we don't want them". So glad I didn't sell.
You realize most people who trade in either don't care about the real value, or really don't have any idea what it's worth?
That's why it works so well. Most kids don't care, hell I never used to. I'd bring a stack of games with me just to get a cheaper price on a new game.
I was actually really tempted (and still am) to put an ad in the newspaper to buy retro games because i'm quite certain i'd make a killing off of peoples ignorance.
I used to work for Gamestop, and prices have always been based on supply, not how "good" the game is. The really hard to find and/or niche games are usually relatively high-value trades. But Madden games are always garbage unless you're trading in the current year's game at least a few months before the next one drops. But regardless of the game's value, Gamestop only pays you around 20-45% of what they're gonna sell it for. So bear that in mind, the "value" I'm talking about is all relative to what Gamestop pays for any game, on average, which is
never as much as you'd get selling it to a customer yourself, like on eBay or whatever. But ain't nobody got time for that. Hence, Gamestop's used games revenues.
The prices and trade in values always correspond to how many copies get traded in company-wide, so some cult games are worth quite a bit. Not many people own them, those that do don't want to sell them, and those who want them are willing to pay what they're worth. Old Pokemon games: always valuable. People tend to hang onto them, and they're always in demand. Whether it's some kid wanting to play an old Pokemon adventure he missed out on 'cuz he was a fetus at the time of release, or a competitive player wanting to breed a legit Clefairy with Soft-Boiled, there's always someone willing to pay $30+ for them.
So it's mostly based on supply and demand, not necessarily quality. AAA titles usually end up going in the bargain bin within a year since so many people bought them and traded them in for other big releases. So sometimes that's pretty cool when you're buying, not so much when trading. Like, Borderlands 2 (non-GotY) is only $5. If you traded it in you'd
maybe get $1, the less the game's worth, the less % they'll give you. That doesn't mean it's a crappy game. It just means they have too many of them.
I learned my lesson working there, I almost never buy huge releases new anymore. Waste of $60. If I just wait a year chances are they'll cost half as much. On the other hand if I want, say, whatever odd game Atlus decided to localize that nobody's aware of, I know to reserve a copy 'cuz it'll be a pain in the ass to find later. Shit's situational.