A few months ago I realized that I had a really good number of personal illustrations
(like the one in this post) as well as some old or rejected images that I was not using any more.
I think having your work available for sale on microstock sites (like shutterstock, fotolia etc)
is a good idea, in spite of the fact that these sites don't pay as much as I think they should.
You still get to expose your work to (more) potential customers, motivates you to practice
more (so you can upload more images), show you unique art style, and maybe, if you
are lucky (like Alex Mathers) Google will hire you!!!