It's not too hard to buy powder if you have friends who will split the order with you. The companies are usually willing to mix brands and types of one-pound cans of powder. Bulk powder is usually cheaper still, but everyone has to agree on the brand and granulation, and someone has to go get it; it won't ship. Also, this notice appears to be pretty common: "No more than 50 pounds of powder sold per adult. No more than 100 pounds of powder loaded per vehicle."