Braz-you didn't overpay - you chartered the taxi. When flagging a route taxi, especially on the beach road you need to make it clear you want a "local" fare, meaning he should stop and pick up other passengers as you go. You don't negotiate price - you hand him the local fare of 140JMD. I've learned not to tell them where I'm going - when I get there I say "one stop driver" and that's it. I would imagine on the beach road its a bit tougher as a visitor to try to wrangle a local fare from a route taxi but it can be done.