Nothing. I never buy anything because the one selling it tells me I should.
A new slow cooker, because my old one stopped working on Friday. If not for “Prime Day”, I probably would have placed the order Saturday night or Sunday.
I just got a message today that I had to approve a shipping delay and they don’t know when they will be available. 
While many of the deals were only adequate, if you have a wishlist or watch list, it was a great time to see if any of your items dropped in price.
There were some great deals. Not really all that many, but some.
I was on some tedious concalls and wasted time surfing. I bought some crap that I “need” that was marked down like a ipad power chord, egg slicer, wireless earbuds, can opener, cacao nibs, Himalayan salt lamp, electric hand mixer, and a fitness tracker. Maybe save $40 versus the regular price for all and entertained me during the concalls.
I also go to DSW shoes occaisionally, head back to the big markdown section in my size, and pick up seriously marked shoes if they happen to be what is on the list.
I bought forty-eight pounds of kibble, a new leash, two boxes of Triscuits, a bag of pretzel sticks, a package of frozen sweet and sour chicken, a package of tater tots, a chocolate cake, a half gallon of milk, and a twelve-pack of Stella Artois. And based on when my sister charged my debit card, two pounds each of peanut and cashew brittle, a dozen muffins, and a pan of baklava.
What’s Prime Day? Shouldn’t it be on a day that’s a prime number?
I posted a question here about repainting a microwave due to rust. An article referred to in response pointed out the risk of microwave radiation leaking out if there were holes in the metal. Since the rust in my microwave was pretty deep I decided to buy a new microwave. So I bought one at the Target Prime Day sale for a 25% discount (as well as 5% Redcard discount).
What the heck does Prime Day have to do with Target?
Thread title: “What did you buy on Prime Day? (not strictly limited to Amazon)”
I was responding specifically to this (my bolding.)
Yes, and I was responding to you responding to that.
Target had a sale during the Prime Day Sale to compete.
A lot of companies had sales on Prime Day.