Update: Going in and out of stock, if you missed it earlier. Walmart is competing with Amazon in a big way though with a Switch + game of your choice bundle for $322-$329, depending on the game. Your options are really good, including Super Mario Odyssey, Breath of the Wild, and Mario Kart 8.
It’s not quite a Nintendo Switch discount (those don’t really exist outside of eBay sales), but this Prime Day deal is pretty darn close. Pay the regular $300 for Nintendo’s latest and greatest console, and Amazon will throw in a $20 eShop gift card and a 64GB microSD card, for Prime members only. Those bonuses are worth roughly $40.