Making electronic music. You can get lots of software tools for free, so I started out with those.

Then I realized how many details get lost, depending on what speaker/headphones you use, so bought myself higher quality headphones. As in, quite high-end for normies, but obviously, I'm at the lower end for music production hardware.

Now I'm considering buying a MIDI keyboard, because those software tools don't quite emulate proper piano playing. Although, you could obviously also spend money on getting different software tools. And of course, on a quadrillion plugins for these software tools, to produce different sounds.

I'm just glad that my other hobby is programming, so when my music-self gets excited about an idea, my programming-self will want to solve it.
...and then never finish what music-self wanted, but at least we're distracted from spending money.