However even leaving out some death penalty costs, the death penalty ($1.7 million) would still likely have been the more expensive option than life in prison ($1.3 million) for a hypothetical guilty verdict for Kevin Harper.etitions? = $1,028,700+ MORE than a non-death penalty case. With the exception of a man convicted last year, the seven Washington inmates on death row now have been there an average of 14 years; add over another half million in prison costs not counting the extra expense of death row.