I came across a great site the other day through advertising on Kottke .  Just to be clear, the site is NOT a sponsor of this blog but I'm sharing this link anyway because I think the products and concept are great.  20x200 works on a simple model:

We introduce two new pieces [of art] 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.