What is your "inexpensive" hobby that turned out to be expensive/ you gradually invested lots of money into?

https://sopuli.xyz/post/2837546

What is your "inexpensive" hobby that turned out to be expensive/ you gradually invested lots of money into? - Sopuli

Self-hosting apps / homelab

Getting used enterprise gear is not prohibitively expensive, but the electric bills balloon very quickly.

I ran a “midrange” Sun at home for about ten years. The electric bill was painful, but I never had to turn on the heat in the winter.
But the summers :(
27°C at home during the hotter days was atrocious.
Yeah, hot days were bad.