I got my first account when Neopets was new. Back then there were more random events. Christmas paintbrushes were found by just walking around in Happy Valley, The Ice Caves and Terror Mountain. They weren't quite as valuable back then for the same reason.
If you are looking to get a paintbrush easily then you should try the wheel of monotony if you have the patience.
I was walking around randomly, and I found a Yellow Paintbrush. Then I was exploring the Paint Brush place randomly, and I found a Christmas Paint Brush.