We could go back to stonings and crucifiction. Rocks and the crosses are reusable and cheap.
On a semi-related note, I'm all in favor of public executions. The halftime show at the Super Bowl should feature at least three sociopaths getting hanged, fried, or shot. Lethal injection just doesn't make for good TV, though the gas chamber might be OK if the chap inside it twitches and convulses a lot.
I'd rather them be beheaded, and have the heads roll into one of 5 numbered holes so that the people can gamble on which hole the head will roll into.
Decapitation Plinko!