Annie's Annuals 801 Chesley Ave. Richmond, CA 94801 (888) 266-4370 (No charge to call.)
Free recycled potting soil is available at the back of Annie's Annuals.
(Call ahead of time to see when, or if, soil is currently available.)
Free Soil Field Book
There is a free downloadable soil field book on the USDA website. It was put together by the National Soil Survey Center, the Natural Resources Conservation Service and the U.S. Department of Agriculture. The book includes all kinds of information about soil, and how to take soil samples.