MakerJuice sells its G+ resin for $55 per liter. I think there are other discount resin suppliers, but I've personally used Makerjuice and am quite satisfied with it. The Form 1 is pretty top-of-the-line, but there is also the Pegasus Touch, and soon (December) there will also be the Titan1 which are both comparable to the Form 1 for a little bit less cost. For a lower-end printer there's the LumiFold (which should be up for sale soon, they also sell some very cheap resin) and on Indiegogo there is the LumiPocket. Also brand new on Kickstarter is the iBox Nano which is admittedly probalby not what you're looking for, but it sure is cheap. For the cheapest, open-sourced, DIY solution ($99 for a kit where you still have to supply some of the simple parts), there's the Peachy Printer, which is up for pre-ordering and should ship around July.