I use Medibang for Hybrid Society. It’s 100% free and has lots of comic making tools. It also have screen tones for anyone doing b/w comics.
I have a free copy of photoshop which I sometimes use for editting art and comics but I km terrible at drawing on PS because there’s no stabiliser and I have super shakey hands lol
I used to use SAI but it’s very outdated now and doesn’t work well with my Surface Pro. SAI 2 is meant to work a lot better and have tools for creating comics but I haven’t tried it and don’t really have a desire to since I downloaded Medibang.