[Silver is usually a pretty patient person, but this lady is really pushing his buttons. So what's a guy that is standing right behind her going to do?]

Hey, lady, maybe you're not understanding what's going on here. The coupons are like you. Cheap and expired.

[The lady stops and stands aghast for a moment before launching into some tirade about how this has nothing to do with him-]

Your words are like your coupons too. Big in quantity, but totally worthless. Your attitude needs a discount.

[...It's hard to tell whether she's embarrassed for herself or because those were the lamest one liners imaginable, but it gets her to shut up and pay, at least.]