1. 2018 Tesla Model S used 12k pre-Elon going full Elon. ($45,725) was a huge purchase and most expensive car ever but gas savings for my 120 mile daily round trip to work saved me over $400/mo.
2. 12ft trampoline. ($200). Kids love it, wife and I love it. Also shows me I’m getting old when random muscles tweak on me.
3. Second hand rocking chair from early 1900s ($45). If you haven’t rocked in a chair that was made only for that purpose before it became wholly automated, you should. Can’t figure out if it’s the arc of the rockers or what but it’s more relaxing than the $279ea set of porch rockers we have.

The good windshield washer fluid. The stuff that's a dollar or two more expensive. Rain basically jumps off my windshield, and I don't need my wipers above 50 unless it's really raining hard. When I actually do use my wipers, they work so much better.

Bought a lot of CDEV (Now PR) stock at 50 to 75 cents in March 2020.

The profit when it rebounded Post-COVID paid off my student loans and covered the down payment on my condo.

100% the best purchase I ever made.

Seki Edge fingernail clippers were the first thing that came to my mind.

Recently got a bidet, it was a cheap one to see if I'd like it. Now I'm thinking of getting a better one.

A Ducati Desert X

I got a PowerMac G3 with a 1994s Apple keyboard and a 1996s apple mouse, full functional,fooorr.. 10€. My best deal ever!

This is a little more niche, but as a hobbyist guitar player, I've wasted a ton of money on gear that had some use, but was mostly redundant or not all that necessary.

But the best purchase I ever made for guitar gear was a Digitech Trio pedal. There was a blow out sale with one of the major music vendors and they were just giving them away for $50. I don't get a chance to play with other folks all that often, and especially over the whole Covid lockdowns, this thing made at-home play/practice just the most fun thing ever. The pedal generates drum and bass parts that will fit whatever chord progression you feed it, so it just fills in the whole rhythm section and you can do whatever you need on top of that.

It gets more use than any other piece of gear I've ever had.