I scrounged all my materials for this kiln.
I didn't have access or the money to buy a bunch of insulated soft brick so I used hard fire brick for my kiln, about 50 full and 10 split brick. The bricks are very loosely stacked and the fire box and firing chamber are one in the same.
I used an old refrigerator grate in the fire box to hold the wood, and the kiln lid is a scrap piece of hard fiber board that was given to me by a local furnace repair business.
The wood is from shipping pallettes that I get for free. I just have to pick them up and saw them up with a skill saw. I then split the wood into small pieces.
It takes approximately 3 pallettes and a couple hours to fire the kiln. I haven't yet fired another batch after the first initial firing but imagine subsequent firings would take about a half hour.