Fabric Depot has everything you need to make virtually anything for the home. In addition to a huge selection of fabric at reasonable prices, they carry foam and other upholstery equipment, pillow forms, lamps, drapery hardware, patterns and much more. Watch for their 40% off sales. Their fabric is either 25% or 30% off everyday, but occasionally they have 40% off weekends.
If you need help with a project, ask around until you find an experienced sales associate. Carefully check the fabric before you buy it. I often find flaws in the fabric. They do take returns if the fabric hasn't been cut yet.