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?
My Sony WH1000-XM3s started turning themselves off after a few years. Their noise cancelling is probably better than others but I can’t say they’ve been reliable.