Indulge yourself, sure. But if the item in question is part of a fleeting trend (especially if it’s really annoying and bound-to-be-short-lived), never spend more than 40 bucks on it.

Application # 1
The aviator-sunglasses trend.

Look! 10 bucks!

Application #2
The stupid skinny-belt trend.

G as in Guillermo?

Application #3
If imitation is flattery, then Louis Vuitton is blushing. And your locks are that much better for it. (Available at Urban Outfitters, 374 Sixth Avenue, 212-677-9350).

Application #4
Military? Like they don’t know from bargains? We say, do it Uncle Sam’s way.