1 The death penalty costs more than life imprisonment. 2  It costs taxpayers from $2 to $5 million per death sentence for the trials and appeals. 3  Life in prison averages $1 million (40 years at $25,000/year). The death penalty costs more than life imprisonment. 2  It costs taxpayers from $2 to $5 million per death sentence for the trials and appeals. 3  Life in prison averages $1 million (40 years at $25,000/year).