I know this is a popular topic nowadays, but you always must be wary about sales on Amazon and otherwise. If you know the going rate for an item, then you could definitely find deals on Prime Day.
I purchased Levi's 511 Rigid Dragon for 27.99 USD that day, and this bed frame for only 139.99 USD. Those deals are not likely replicable except on very specific days of the year. I don't monitor deals every day, so it was nice for me to save 50+ USD on items I needed anyway.