If you're talking about a nation where post-conviction, the convict is just taken out back to the gibbet, yeah that's cheaper, but otherwise, no... death row is insanely expensive. You have to pay for the requisite appeals and all the legal fees that go with it. You have to pay for the solitary confinement. You have to pay for round-the-clock guards, who make more than other guards because no one wants to actually hang around with murderers and they need a financial incentive to care about things like suicide watch. The guards are working in a depressive, dangerous environment, so they have more physical and mental needs when it comes to health care. You have to pay for all the non-guard workers like doctors, nurses, and other staff who also get an increased pay and increased benefit needs, who are, again, working in a depressive, dangerous environment. You have to pay for the health care of the inmates, because you have to keep them healthy until the day they are executed, and many of them have a lot of mental issues and require drugs and therapy, again with the help of premium staff. You have to pay for the automated and non-automated security systems, including cameras, DVRs, multiple locks of sliding gates, and other facilities. Sometimes you even have to maintain a separate armory and commissary if the death row facility is heavily segregated from the main facility. Hell, even getting someone from one side of the facility to another takes a very long time because of all the security checks and preparations that need to be made, because no one is tolerant of any risk when it comes to handling prisoners.