Those "epic deals" are mostly scam. I've looked at different stuff, and e.g. the beyerdynamic Amiron was supposedly 30% off or sth. but that was just the normal price for months. Same with TVs, just the normal price that sits well below MSRP suddenly praised as "Prime Day Deal". Genuine reductions are usually merely ~5% and for e.g. blu-rays and stuff.
The only two things that were truly cheaper I found was a Brother printer, which went from 250€ to 200€, as well as a 9k BTU Monoblock AC (300 -> 230. Completely sold out within a day). All the other things were not worth it or just lies.