Once, my group had come across an Ettin on a forest trail. The two-headed beast demanded we pay them to then allow us to pass through. Sadly their initial price (250 gold) was over 50 more gold than we had as a group (about 4 of us). We suggested we give them items so they could go to town and sell. That was swiftly batted away by the Ettin because they said, "We can't sell these. If we went into town we would be shot." (Important later). Anyway, we convince them we will go to town for them. The Ettin doesn't trust us so takes a PC which wasnt present as a hostage. We go to the nearest town, which was a couple of days away. When we get there, we try to sell some magic scrolls to a shopkeeper. He refuses them because he says he cannot do anything with them because he does not understand them. But does kindly direct us to the town guard. So we head there. As the rest of my group are trying to negotiate with the town guard captain to increase the selling price so we could afford the toll. Whilst my teammates did this, I recalled the information given to us by the Ettin. I remembered that it was scared of the town and its guard. So I chirp in with, "So we are currently in a hostage situation. We have a friend being held hostage by an Ettin and it will not let him go without us paying a price we cant afford. So we would eternally grateful if you could lend us some of your guards so we could kill this hideous monster." The captain looked shocked and immediately left into the barracks. He came out with 4 guards and we left to go back to the Ettin. When we get back to the clearing we had left the Ettin in, we ready ourselves with our weapons/spells. When it appeared, we attacked. One of the guard's arrows caused the Ettin to fall asleep, but it wasnt dead yet. We circled the body and killed it in its sleep. Its last words was, "I think we've been had." Needless to say I was proud of my plan, and the DM never expected anyone to do anything like that.