clip studio paint is really great for comics! its a one-time buy, and they have sales really often when its just $25. unlike photoshop, its built from the ground up for comics and illustration, which is really beneficial.
ive also used paint tool SAI, which is pretty great for what it is and also pretty cheap.
a lot of people in the industry use photoshop, and if you have a chance to get your hands on it (through school, work, a conveniently placed crack) its worth getting to grips with and it has a lot of advantages as a software, but it is priceeeeey