Don't get into keyboards, I have multiple keyboards, most expensive one I spent $300 to build, the one I am using now is $150, and I have a few others in that price range, and one that is half built
I almost picked up a $60 keyboard impulse buy for my wife today. Then I thought that she is using the $300 one, but she wishes the key caps were pink, maybe $60 is reasonable just for the key caps? No stop it
Similar things like fighting sticks, I don't want to talk about it
For paid hobbies, 3d printing isn't that awful, as long as you learn 3d modeling while your at it. It's a bit of a cost, after that the consumables isn't horrible, and I can leave it for a while and come back a few times per year, and it can mix with other hobbies.
I enjoy programming! It's free, and I can hyper focus on a programming project, and if I move on I can move on to another programming project.
I usually try to get at least a few YouTube videos in before going to bed after programming. Because if I hyper focus on programming and then go to bed, I will wake up in the middle of the night with a solution to a problem I had. While that is great fun, I have enough issues getting enough sleep as it is, don't need to wake up at 3AM and having to get over to the computer to write down an algorithm or something, then test it, then post about it online because I am so happy and proud and can't get back to sleep
My brother will get into expensive stuff, and then he can't finish what he starts, and his hp proliant server is still collecting dust in his spare bedroom.
My father would have projects that he needed to take up additional mortgages for, like buying a fish selling truck (why not ice cream ffs), or a boat, or shit. Or buying farming equipment even though he has a lawn sized lawn and not a field sized lawn, or a boat or shit.