A murder trial normally takes much longer when the death penalty is at issue than when it is not. Litigation costs - including the time of judges, prosecutors,public defenders, and court reporters, and the high costs of briefs -- are all borne by the taxpayer.
A 1982 study showed that were the death penalty to be reintroduced in New York, the cost of the capital trial alone would be more than double the cost of a life term in prison.(50)
In Maryland, a comparison of capital trial costs with and without the death penalty for the years 1979-1984 concluded that a death penalty case costs "approximately 42 percent more than a case resulting in a non-death sentence."(51) In 1988 and 1989 th e Kansas legislature voted against reinstating the death penalty after it was informed that reintroduction would involve a first-year cost of "more than $ 11 million."(52) Florida, with one of the nation's largest death rows, has estimated that the true cost of each execution is approximately $3.2 million, or approximately six times the cost of a life-imprisonment sentence.(53)
The only way to make the death penalty a "better buy" than imprisonment is to weaken due process and curtail appellate review, which are the defendant's (and society's) only protections against the grossest miscarriages of justice. The savings in dollar s would be at the cost of justice: In nearly half of the death-penalty cases given review under federal habeas corpus, the conviction is overturned.(54)"
I suggest you read the rest because you don't seem to know enough about this to have a well-informed opinion on the subject