If we were going to set out on this adventure, we wanted to do it as cheaply as possible, but still do it in a way that the chickens would be safe, warm, happy, and productive. After brainstorming for a while I came up with the idea to use our old garbage bin for a coop. The sanitation department now requires us to take our trash to the end of the drive, so the bin has been unused for a while. Michael agreed that we could make it work and save a bundle at the same time by not having to buy any materials to build a coop.
Here is the bin we decided to use.