In Texas a death penalty case costs taxpayers an average of $2.3 million, about three times the cost of imprisoning someone in a single cell at the highest security level for 40 years. In Florida, each execution is costing the state $3.2 million. In financially strapped California, one report estimated that the state could save $90 million each year by abolishing capital punishment. The New York Department of Correctional Services estimated that implementing the death penalty would cost the state about $118 million annually.
source: The Death Penalty Information Center, "Millions Misspent: What Politicians Don't Say About the High Costs of the Death Penalty," October, 1992