If it's obvious that they're guilty (dna, cctv etc) then I can't think how it could possibly be more expensive. I mean I understand that it can be for the reasons PPK stated, but if it was done properly, who could it be? If they're definitely guilty, there's no need for an appeal, just shoot the bastard or strap them in and inject them. That would definitely cost a lot less than another 50/60 years worth of looking after them