I made three of the Flash Ovens this past weekend, one for my brother and two for me.  They weigh 12 oz (each) including skewers, heat diffuser, and oven thermometer.  Home Depot has various height rolls of aluminum flashing from 10" to 20".  Betty Crocker has some muffin mixes in a bag that cost $1 and all you add is 1/2C water.  I made the lemon poppyseed (small) cake from the mix and it turned out great.  Easy to make, cheap, and works good.