I found 20x200 through the blog A Cup of Jo and I think it's the best affordable art resource I've stumbled across in a long time. They introduce two new pieces a week: one photo and one work on paper. Each image is available in three sizes. The smallest size is reprinted in the largest batch—an edition of 200—and sold at the lowest price ($20). Hence the name 20x200. Bigger prints are available for bolder collectors—medium-sized editions of 20 for $200, and large-sized editions of 2 generally for $2000. In other words: large editions + low prices × the internet = art for everyone! Check it out right here.