To buy custom brushes from artists here. Now that I'm using Clip Studio Paint, and there are many wonderful brushes!
Thanks for the llama badge! I'm pretty new here and that kind of encouragement really helps! Your badge (my tenth) turned my other badges into a super llama or something - I have to look into what that means but it sounds pretty awesome. Your art is really charming, by the way! I mean to start favoriting works like yours soon - just need some time to look around instead of just submitting stuff really quick and jumping off. Cheers!
I don't really know 100% how the llamas work, never really paid much attention to it. I think you can trade a number of them for points to make internal purchases here.