I'm thinking of starting with whatever's cheapest to freely waste paint while experimenting. I'm guessing acrylics would be it but I haven't been to the art store yet. It's very close by.
I have plenty of experience drawing digitally, but I never managed to get a feel of using digital oil/acrylic/etc brushes, always opting for cel shading instead. In the future, I'd like to make a painting to sell or display somewhere, just for the achievement.