Copic markers are so expensive for several reasons. First of all, they are professional quality markers. They are also durable, chemical-free and odorless. They come in several different nib shapes and sizes and can be found in many different, unusual color varieties that other types of markers don't have. You can replace the nibs on these markers, and they make blending colors much simpler than when trying to use other marker types. However, one of the biggest reasons copic markers are so expensive is because they are refillable. Considering the markers cost about $5 each and the refills cost about the same, that seems expensive. However, you get about nine refills out of the refill tube, which makes the price seem much more reasonable when you consider you're practically getting ten pens for $10.