Humane but Deadly

With the Steven Oken trial finally winding down to his execution, I keep wondering isn't there a cheaper way of executing prisoners, that is also humane?

Infact, there is.  It's called a firing squad.  All you need to do is medically put the destined-to-be-dead down (like he was going in for surgery), and then pump him full of lead.  He won't feel a thing.