It SHOULD be. The additional expense is entirely due to endless appeals, with lawyers paid for by the taxpayers, and mostly on technicalities rather than on the question of whether or not the convicted person did the deed.
However, I do respect the guy who is currently appealing the methods. He's not asking not to be executed, he's asking for a reliably painless method such as is used to euthanize pets. Not a frivolous request by any means, especially given that once in a great while a person gets executed who really didn't earn that punishment. And also something that I think most of us assumed was already the case for lethal injection executions. Who knew that government bureaucracy was capable of screwing up so badly as to approve only one complicated and unreliable procedure, while every vet (and most vet techs) in the country know how to do a reliably painless and very simple lethal injection procedure? More than a little odd, though, that this matter has never been brought to public/media attention by any of our nation's large, large-mouthed crop of self-absorbed anti-death penalty activists. I guess their "great cause" was more important to them than preventing the needless suffering of some actual people who are facing imminent execution.
Please name even one innocent person who has been wrongfully executed.