Meritline offers this Metal Whistle Keychain for $2.49. Coupon code "MLCKX07QNL1" cuts it to 59 cents. With free shipping, that's $3 under the lowest total price we could find for a similar item elsewhere. Whistles such as these work well for emergency self-defense or finding your friends in the Mall of America. Coupon expires after 400 uses.

Expect this item to take two to three weeks to arrive.