Mac, it ain't the needle and death cocktail that costs a lot. It's the 10 years of hearings, motions, re-investigations, reviews, appeals, etc. Basically, the anti-death penalty crowd has made it so costly to execute a death row inmate, it's become cheaper to keep them off death row.
A couple of states are now suspending death sentances due to budgetary constraints.
It's economics, used as a weapon to defeat the political will of the people.