I think the most useless thing I have bought recently was a $350 turntable.   I had a bunch of vinyl records, and I figured I would play them if I had a turntable.   So I bought this turntable, and not only were the vinyl records all full of scratches, but within 2 weeks I had discovered a great streaming service that had all the same music times a thousand, at much better sound quality than I could get from those old vinyl records.   So there sits that turntable, unused.  

Another useless thing I bought was an electronic keyboard.   It didn't cost much, maybe $200.  But I figured I would learn to play the piano.  I got some piano lesson books, and I started in, and got a little ways, but as soon as things got difficult, I quit, and now, there sits that electronic keyboard, in one of my rooms, gathering dust, a permanent symbol of my failure.  I can't go anywhere in the house without passing that thing.  Obviously, I need to donate it to Goodwill or something.  

Then there are things I bought on a whim that turned out to be really useful.   I bought a little Bose bluetooth speaker.  It's about the size of a book.   We put it in the kitchen, and we have music every time we eat dinner.  Right now, as I type this, my wife is doing the dishes listening to music.   Bought it on a whim, and it's a great thing.

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