Since someone already mentioned dashcams and cast iron, my vote is: a bidet toilet seat attachment.
Fancy ones can roll $200+ but a super simple one with just a cold water hookup and no electricity will knock you back $50-60. I bought one right as covid was beginning to hit the west coast, and instantly realized I could never - ever - go back.
Huge bonus of the toilet seat style bidets is that, since you aren’t actually replacing the toilet, they take like 5 mins to install and can be done in a home, condo, apartment, wherever.
One of my favorite jokes ever (forgive the dated lingo)
A code reviewer walks into a bar.
…runs into the bar. …skips into the bar. …handstands into the bar. …does the hula into the bar. …brings four people they just met into the bar.
And orders: …1 beer …10 beers …99999 beers …null beers …a Pepsi …a 10" personal pizza …4 orders of salted peanuts …DROP TABLE orders of salted peanuts
Nothing goes wrong.
Another person walks into the bar and asks to use the bathroom.
The bar goes up in flames.
*Edit - I forgot the drop table peanuts
Not verifying the load capacity of a customers vehicle.
My past job made the customer sign off the paperwork before we loaded them up and this guy did sign off on the paperwork that his truck could take the load. So, I wasn’t technically liable. I was newly certified and was the only driver around that day. We were a small shop that only took a few deliveries a week, and customers wanting samples back after delivery was even rarer (destructive testing is fun!).
Since I was new to this, I didn’t intuitively know the difference between a flatbed and a normal passenger pickup. So yeah. In my ignorance and with this guy’s sign-off in hand, I try to load his ~1000lb pallet of bigass metal test samples into his. Personal. Pickup.
The truck just kept squatting and squatting, even though I still had weight on the forks… until it finally made a horrific creaking noise. I immediately unloaded the pallet and went to apologize. The guy was mortified but he kept it cool and called his actual delivery guy to come with a flatbed the next day. I did that one too, thankfully his delivery guy just cracked up when I explained what happened (even gave me some quick advice too!). They kept doing business with us, at least, but his reaction in that moment is still seared into my mind.