Justice on a silver platter

Today in class I was asked what form of justice should be done to criminals. The same be done to the criminal as the criminal did to another person, or some other form of punishment that might not be near as bad. This is hard because I see the pros and cons of both sides. I think the same be done to the person would be good in most cases and would threaten criminals, but I don't think it is right for us to kill, even if the other person sees it fit. That's where the other form comes in. if someone gets killed, they're sentenced 15-20 years in jail. If the person killed several, the number gets lengthened by 10 years. Of course this doesn't include everything. A friend asked, "What if someone sells drugs? Do they just get drugs sold back?" Although he said it jokingly, this brings up a real point. If something like this happens, they should be sent to jail or given a fine dealing with the seriousness of this.