yo yo yo.if ya wanna try free drawing programs on computer there are 2 i can suggest:
1. Firealpaca.. kinda like painttool sai.. but completely free..
2. Deleter CGillust... you cant save stuff with this cuz its a demo ( you can always take desktop screenshots though XD)..
just download them from google.. these are completely free and I don't think hey take up much space! Goodluck and enjoy drawing ;3