Just putting in a word for Gimp and Inkscape. The Gimp site doesn't seem to be loading at the moment (wouldn't you know it?), but no doubt it'll be back soon. Here is an alternative download site for Windows. They are free open source equivalents of Photoshop and Illustrator respectively, and available for Windows, MacOS and proper operating systems Linux/Unix/BSD.
Hey, Mac OS X is BSD.... (it's one of the main reasons (no joke) that I switched to it years ago)
I don't use Gimp since I have used Photoshop for a very long time and will probably continue with it. But while I have Illustrator as well, I've started using Inkscape, as I'm trying to avoid the Adobe subscription deathtrap for everything except my essentials (mainly photography) and I don't have a ton of time invested learning Illustrator at this point. Inkscape seems very capable for my needs so far.
The reason I started using Inkscape was related to this forum. Someone had posted a few months ago about Adobe Shape (iOS/Android) as a fast way to vectorize calligraphy, and I tried it out, but I wanted to get the results on to my laptop in SVG format. I finally figured out how to get them out of the Adobe cloud, but then the files wouldn't open in Illustrator (it actually crashed). I downloaded Inkscape, and it opened the files just fine. So I just kept using it.
There's a Skillshare class on Inkscape that I'm planning to check out soon.