Just traded a couple of games and was surprised by the 50% extra on top. Got $32 for Resident Evil: Village (PS4) and $22 for Marvel's Avengers (XBox One). If you don't have Pro membership, it will be $30 and $20 respectively. Asked the employees about the promo and they didn't know what's going on other than "probably an extra boost during Cyberweek". Can't find anything in the last few Gamestop marketing emails and not sure how long this will last and if same applied to controllers and accessories like earlier promo, so if someone can confirm, that would be awesome. Here's the link to RE trade values.
I usually just browse the trade list and see what I have worthwhile that I may want to trade: