GIMP for paint/draw in raster type work.
Inkscape for vector illustration type work.
My Paint a raster paint application that mimics natural paint methods.
PhotoPrint for versatile printing options.
Hey, I didn't do that intentionally, I just looked down and there it was. GIMP and GIMP, I think that is a sign everything is cool. LOL!! There are a lot of other free or low cost softwares I could have used, but I haven't used any of them and they don't spell GIMP when you stack them.
If you are thinking about learning digital art, there are things to be concerned about. One is that the process is as long as the process using natural materials. If you use a mouse get an optical mouse not one with a ball, better control and precision, no cleaning. Get a mouse with a tail, the wireless ones can lag so the response can be behind your hand movement. The same with a tablet and pen, there can be a lag. In some cases the wireless pen can pick up interference and behave awkwardly. I wish todays pens were wired to the tablet like the older CAD tablets. They were cursor pushers and didn't have pressure sensitivity. Practice drawing with a mouse or pen as if you were marking with a pencil. It will become normalized after many hours, the feel and coordination is different.
The first thing to learn after you're familiar with the program is layers. LAYERS, LAYERS, LAYERS. Even in my life as a CAD drafter, layers were important. Learning layers will save your sanity in doing digital art.
Set time for work and play. When you work, work and when you play, play. Why? if you play you will play a lot, might not get any work done. You see, you are not wasting paper, canvas or ink on the computer, only electricity and time. You might get play happy, still you won't get much work done. In digital art there is a lot of planning going on, a mind to work it out and get it done is good. There is always time for fooling around, experimenting, play. Why limit play time? Get away, do something else. Step away from the machine!