FYI, I tried to purchase the Popper stack via Safari, and was unable to get the purchase links or cart to ever work, with or without ad blockers on two different computers. I finally bought it by using Firefox, but when I went to pay with PayPal, I never saw a way to add the discount code. When I clicked on the button in Paddle that said that I would have a chance to still review my order, it placed the order anyway. Not impressed with either behavior, as I view little details like this as signs of reliability for a developer.