What's mildly infuriating here is OP... People are trying to explain how you could have saved almost 1/3 of your purchase price and you just argue with them and keep shouting from your soapbox.
Unfortunately, price shopping is a part of every transaction if you are trying to get the best deal. If you aren't invested enough to read the largest banner on the shop website to save almost 1/3 of your total, then getting the best price was clearly not a concern when you ordered. Yes, you are expected to do that yourself, just like buying anything else in the commerce system we have been using for decades. It's real boomer/privileged energy expecting that to just be done for you.