22 years ago, when I was in college, I bought a Melitta single cup coffee cone. Don't remember what I paid for it, but considering its equivalent to the one currently selling for $3.99, I'd say it can't be much more than that. I have made countless cups of coffee with it, used it nearly everyday since then except for summer which is iced coffee time. I have a fancy Japanese kettle designed for pour over coffee now but I've used it with nothing more than a saucepan before. It's hard to make coffee for company, but 99.9% of the time, it's just me wanting coffee and it's perfect for that.
I sometimes think about replacing it with a glass or ceramic one, but I worry about breaking it, so I stick with my old plastic one. Best coffee maker ever.
The exact same thing came to mind for me. My college roommate bought it for me for Christmas when we were both broke. Sadly, mine developed a crack, and then it broke all the way this spring when I packed it in my luggage to make coffee while traveling. I did find a stainless steel Hario to replace it with, and think the coffee is marginally better, but that Melitta cone really paid for itself over the years.
Last winter I picked up a very ugly but very solid little book shelf that was left on the curb. It was marginally useful in the garage, but I just moved it down to the basement closet that I use as a pantry, and it fits like it was made for the space, and is perfect for storing winter squashes.