Yeah, it really caught me off guard the first time I used the site. It was during one of those special celebration discount days where they had the audacity to mark items as literally $0.01 when basically nothing was that price.
For 3D printer filament, which is usually bought in 1kg/2.2lb spools, most places list a 2m sample or a 250g spool to game the search. And my other favorite is the whack-a-mole shipping setup where on variation might be free shipping, but choose a different color and the shipping jumps to $300+.
With Amazon, I'm seeing a ton more overpriced items discounted to still higher priced than their competition. If you look at their deals pages, you can find things like portable monitors for $70 (down from $150), but checking that category shows the same monitor (same specs under a different name) for $60.
Here's as close as I can find right now, since all the lightning deals are ending for the day. There's a USB laptop docking station that's "discounted" from $139 to $70. There isn't an exact match (there usually is), but similar products go for ~$60-$70 (2 HDMI, 4+ USB3 ports, 100W PD, ethernet). What's funnier is that the specific company's Amazon site has at least 4 identical docks at slightly different prices.