https://www.amazon.com/dp/B08HB9TCVG/ref=cm_sw_r_tw_dp_x_c.PwFbG1TBXXE

NOt sure when, there are secondary sellers, but they are listing ones bought from other sites.

Other retailers (you mileage may vary)

• Game Stop:https://www.gamestop.com/video-games/arcade/products/game-and-watch-super-mario-bros./11108259.html
• BestBuy: https://www.bestbuy.com/site/nintendo-game-watch-super-mario-bros-/6428471.p?skuId=6428471
• Amazon: https://www.amazon.com/dp/B08HB9TCVG
• WalMart: https://www.walmart.com/ip/Game-Watch-Super-Mario-Bros/576154747
• Nintendo: https://store.nintendo.com/game-watch-super-mario-bros.html