Follow link and add Koala Kids Red Flip Flops (#269BF47C), you can search by that item number. Add to cart and add additional 1 item to cart for 50% off.
Worked on Xbox One X, Xbox One S & a Recliner that I tried.
This is very YMMV and some items will only be available for store pickup.
Update: Xbox One X is showing OOS
Edit: Seems to be working with Koala branded shoes/flip flops that advertise, "Buy 1 Get 1 50% off all regular priced Koala..."