The best place to shop for these devices is the Internet. Try Sweet Maria’s, Coffee Bean Corral, or The Coffee Project.
Green coffee often can be bought from stores that roast coffee on the premises. Simply ask the clerk or proprietor; most will be happy to sell green coffee in bulk for 20% or so less than roasted. The home roasting Internet sites listed above also carry a wide variety of green coffee origins.
Home roasters will find in-depth information about choosing, blending and roasting coffee in my book Home Coffee Roasting: Romance & Revival, published by St. Martin’s Press.