Excellent idea, it never occurred to me to try and sell this on Amazon. I think in the spirit of "bootstrapping" this would be step 2 or 3 on the list due to the start up costs.
I will be the first one to admit that I don't know everything. It never occurred to me, in part, because I had misconceptions about the barriers to entry. Those misconceptions have been corrected because of this post.
Simply put, I thought it would be more expensive to publish on Amazon. :)