You must haggle

[rebbonk]

Two Irishmen are traveling to Australia. Before they leave home, one of their dads gives them both a bit of advice: "You watch them Aussie cab drivers. They'll rob you blind. Don't you go paying them what they ask. You haggle."

At the Sydney airport, the Irishmen catch a cab to their hotel. When they reach their destination, the cabbie says, "That'll be twenty dollars, lads."

"Oh no, you don't! My dad warned me about you. You'll only be getting fifteen dollars from me," says one of the men.

Spoiler:

"And you'll only be getting fifteen from me too," adds the other.

[dutchman]