Used metal 55-gallon drums are sometimes available on local Craigslist.com ads or through a nearby used materials yard. Amazon.com sells new 10-, 30- and 55-gallon steel barrels with and without lids.
CommonSenseHome.com recommends making a safe and virtually smokeless burn barrel by drilling three or four holes in the bottom of the drum and several holes in the side. It advises not to exceed 20 holes, in order to maintain the integrity of the barrel. The drum is set on top of two concrete blocks to provide air flow and drainage. It is important to position the burn barrel downwind of buildings, trees and flammable materials. In addition, one should check with local authorities prior to using a burn barrel.