For the avid do-it-your-selfer there's an alternative: Tiger Foam Spray Foam Insulation Kits. Tiger Foam offer kits, nozzles, even protective clothing. Kits are shipped by UPS freight. Shipping for the 200 board feet kit would be about $75 to San Antonio.
They sell a fast rise formula foam for open applications and a slow rise low pressure formula for filling wall and block cavities. Their closed cell product expands at an 8 to 1 ratio, so that one inch of spray would expand to eight inches of foam.
According to Commercial Thermal Solutions the company behind Tiger Foam:
Tiger Foam® quick curing, disposable, two-component spray polyurethane foam insulation kits are manufactured to ASTM E-84 Specifications and classified as a fire-rated foam insulation. Our spray foam insulation is manufactured using the most environmentally friendly blowing agents and fire-retardant chemicals available today and DOES NOT contain CFCs, VOCs, Formaldehyde or PENTA-BDEs.We are the ONLY supplier offering E-84 Fire Rating STANDARD in our surface spray product line.Technical support is offered by phone. But they suggest that you review the wide variety of information available in pdf form from them before making any purchase. From looking at the site it seems like though they make it as simple as possible, a realistic evaluation of one's abilities would be in order before undertaking such a project.