Programming started as a hobby for me as a teenager. I always "liked computers" so thought I'd give it a try. I never intended to make a career out of it because it seemed so hard at first, but over a decade later, I'm decently accomplished in my field and get paid bank for it.

As a hobby, it's fantastic. You can add in missing features to open source software you use (including the one I'm posting this to right now!). You can make your own little apps to fill niches you haven't found an existing program for. You can automate boring stuff from other work. You can make mods for certain types of video games. Or if you're really ambitious, you can even make a video game (but I gotta tell you, video games are hard and need much more than just programming -- I do not recommend making video games as a goal unless you've thought out just what that involves).

If you make a career out of it later, cool. But even if you don't, it's a fun and rewarding hobby that costs almost nothing. As long as you have a computer (preferably not a mobile phone, though it's technically possible to use a phone), you can program. Hardware doesn't generally matter. Any cheap laptop works. All the tools you need have free and often open source ones you can use. You only need to pay for web hosting if you make a web tool and want to share it with others.