For me, it was a pair of merrell shoes on sale. They have lasted 3+ years, have great grip in the snow and ice, and so comfortable, my feet don’t hurt after wearing all day.
Never cheap out on anything that comes between you and the ground; shoes, tires, a bed.
What have been some of your good purchases under $100?
Basically a flat piece of wood or plastic that can hold your keyboard and mouse, with some kind of cushion attached underneath so that it comfortably sits on your legs. I got this one last year to help with working from home in a comfy chair and it’s been pretty great (Amazon link)…
https://a.co/d/dbrEYtP