Brief, Skippable Preface: I resigned from a job-which-shall-remain-nameless in the entertainment industry in the city (Portland, OR), cashed everything out and moved to 8 acres with my wife to raise our children up on our little permie homestead. A good-to-know (and painfully learned) lesson is that "High End Graphic Designer" is essentially useless in rural areas. Because everyone out here has a brother's-wife's-third-cousin-in-highschool who "does web sites". I'll skip a long story and share the relevant tidbit.
The Relevant Bit: I began working with small farms on their branding and packaging. To keep their costs down, but still produce good work, we agreed that I'd use their projects to build complex Photoshop mockup tools to sell on the side. Never using their artwork to sell of course. So the final presentation of their work was done in a nice little mockup for free which would've normally cost them an extra $400-600 to build. Makes them look professional beyond their budget and makes me look like a super-duper nice, incredible guy... so full of win.
This has done a couple of things.
1. It's allowed me to build a reputation for honesty and for putting in extra effort into every project. I actually DO give a damn and I love building relationships with and helping out local people.
2. I've now been able to pay my phone bill at least for the last few months.
While it's not a lot of money, I'm hopeful and I've several more tools in the works now.
So if you're a graphic designer, you can sell all sorts of digital thingies online at sites like:
http://market.envato.com (photoshop files, dev code, web packages, 3D files, audio clips, etc) This is where I sell my goodies.
http://www.istockphoto.com (to sell your photos)
https://creativemarket.com (photoshop files, vector files, logo kits, etc)
Worth noting for the not-so-technically-inclined artists: If you're not skilled with software, but still have awesome hand-drawn elements that could be used by others, it's still work considering. Designers are always looking for new, interesting hand-drawn textures and elements. I know I've built up a collection of hundreds over the last 15+ years. It's actually a little embarassing now that I think about it.