I'm a bit surprised that you are not aware of the costs.

There is plenty of data to show it is less costly to send a prisoner to jail for life than to execute him. This has nothing to do with actually putting a needle in his arm. The legal process to get him to that point is what consumes all the funds. And, the taxpayer gets to pay for both the prosecution and the defense.

I'm for the death penalty in certain specific cases. However, if I can pay less and lock them up for life, I'm fine with that too.