For those who don’t already know those sites, here is some ressources to earn a little money as an artist on the net.
First there is Ebay were you can sell pratcly anything. It’s a good place to sell your original artwork. I’ve personally done it for a couple of years and i was selling some drawings praticly every weeks. The down side of it, is you’re probably gonna have to sell your art for less than you would have wanted. On the other hand by times some peoples can ask you for comissioned work and on the long run you can build a regular clients network.
Secondly there is Zazzle.com and cafepress.com. There you can put your artwork on differents products; T-shirts, prints, muggs, magnets, etc… Once you’ve created an account there you can upload your images on their site and peoples can buy the products directly there. They take the orders, print your art on their products, and ship it. Then you earn royalties on their sell. A little problem is there is so much interesting designs already there that you will have to find a way to draw traffic to your gallery or store if you want to earn something worth your effort.
Third, for books. Lulu.com are a ressource for self publisher and work in a similar way as cafepress or zazzle once they have the pdf of your work. Meaning a good way to test how your artbook or comicbook will sell on their marketplace, without doing any investment. Also, once you have an i.s.b.n. you can sell in online bookstore and to libraries.
There is a lot of other sites who propose simillar things or who can be interesting to promote your work but those 4 sites are some of the most important on the internet, and in my opinion, any artists should, at least, know they exist.