This. I also buy way too much stuff from Amazon. I recently got a new bike, which has meant an ever growing list of dumb accessories to go with it (e.g., I got a Brooks leather saddle, but when new they require occasional tightening, and it's a pain to get a regular spanner wrench in there. Brooks makes a $15 spanner for precisely this one purpose... so I bought it).

Along the way, I've sometimes gone price shopping elsewhere prior to hitting the buy button and the results are illuminating. Amazon will sometimes be right in the middle of the pack. Sometimes (particularly with oddball bike parts) they'll be notably higher than the pack and sometimes notably cheaper than anybody else anywhere. It's a total crapshoot. If you're buying $200 of assorted bike parts, for example, Chain Reaction will often blow Amazon away. But if you're buying a $15 part, Amazon might well be the cheapest.

One other random anecdote: a couple years ago, we had a minor disaster when it turned out that the pan below our shower was slowly leaking, which basically required going all the way down to the studs and rebuilding the shower. We decided to use this as an excuse to upgrade our shower to have his-and-hers dual showerheads. We went to a local shop that specializes in this sort of thing and picked out a particular set of Hansgrohe hardware which came with an eye-popping price. I was able to buy exactly the same gear on Amazon for maybe 2/3 of the list price. Win!

Back to the original point, I generally don't have standing orders where I can patiently wait for a discount, and if/when Amazon plays these Mac vs. PC profiling games on me, I'll almost certainly fall for it. I suppose somebody could make a browser plugin that warns you when Amazon is trying to screw you. That could be entertaining to build.

There's another mode of Amazon failure that's worth noting on this thread: when Amazon runs out of something and the only seller with stock is a third-party with a jacked-up price. This reared its head over the holidays when I had a particular pair of pants on my Christmas shopping list, in an odd size (33" waist). Amazon ran out and the offering price was 3x what the pants should have been from the only vendor who still had them. I suspect this sort of thing is a deliberate strategy to profit from people who literally don't look at the prices and just blindly buy anything.