HERE You can see EBGames has MK8 Deluxe, Arms and other accessories listed under "Switch: All" For whatever reason you can't see these by just going to the switch page and then going to games. Currently EBGames has a few decent trade in deals which can be seen Here I'm mainly referencing the 6th and 7th promotion. Currently certain Wii U titles are worth quite a bit, for example you normally get $25 for MK8 but if you trade it towards anything switch UNTIL TOMORROW you get 2x the value making it worth $50, so basically you can trade it in now and have $50 off MK8 Deluxe. A lot of Wii u games have pretty solid value and being doubles you can get $50/$56 for certain titles.
Next the promotion that says "Trade 3 for 1 new switch game" So basically any game That's worth at least $8 trade in You can trade three of these in and get an $80 title free! Personally I've been able to go to a local Pawn shop and find a few titles for about $15/$20 each and then just traded those in.
Anyways just thought I'd post this because the people at EBGames let me pre-order MK8 Deluxe through trading in so ARMS May work as well and it's one of your last two days to trade in games Like MK8 for 2x the trade credit.
Discussion started at here by RipSkinsByBet