We went on a tour of historical Bagdad, FL today and I found some really heavy canvas at a church rummage sale.  It's about twice as thick as the stuff you find in fabric stores and tightly woven.  I'd say there is 2 yards of 60" wide and I paid 75 cents for it.  I think I'll make some 1860s style haversacks with it.  I also found a pair of 1880s spectacles that I can read with for $15.00.  The temples aren't exactly right but the lens shape and bridge is correct for the Civil War period reenacting.