I have 45 markers and I bought the first half at Anime Expo this summer, and the second half at an art supply fair at my school. There are places online where you can buy them, though. Each marker is $5, so they can be expensive to collect, for sure. The thing I like about copics as opposed to prismacolors is that you can blend them super easily, especially if you have marker paper. So, even if you only have 12 markers, if you get the right colors it's possible to make many more colors just by layering.