Seriously, stop with the Ebay & Craigslist crap. Some of us don't give a crap, if we didn't we wouldn't be posting here in this thread and trading at GS. You want to sell elsewhere, by all means.. but stop telling others what to do. It got old years ago.
Assuming we've played the games we bought, any trade-in at all is gravy to me. Sometimes I sell my games outright if it has value, but honestly that value had diminished for the most part these days as games go on sale at huge discounts so quickly, where you could sell a big new release for $40 3 weeks after you bought it, it's usually on Amazon for that price at some point... it's just easier to find a good promo at GS and get $30-35 in credit.
It's easy, and I don't have to mail it, hope it doesn't get lost, someone doesn't rip me off, whatever.