Season 4, Episode 12: "The Airport"

If anything, we'll probably get there early.

I'll have a chance to go to the duty-free shop.

-The duty-free shop? -Yeah.

Duty-free is the biggest sucker deal in retail.

-You know how much duty is? -Duty?

-Yeah. You know how much duty is? -No, I don't know how much duty is.

Duty's nothing. It's like sales tax.

Well, I'd still like to stop at the duty-free shop.