I hate coming home to Georgia during the summer because it's hot and muggy as balls—granted NYC sidewalks in the summer make you feel like you're walking on a clay oven. But Osaka's Kiribai Chemical Co. has us covered with its canned "ice spray," which blasts 14-degree (F) frost into your face (you're supposed to hit a towel to wipe your face with, but whatever—frostbite feels fine right about now).
The spray works out to a little under 10 cents a shot since it boasts 70 pumps per bottle at two second intervals and runs about $6.50 a can. Or you could buy a three-dollar bottle of canned air, turn it upside down, and my guess is get more or less the same effect—I've frozen many a foe (and friend) with my ghetto Mr. Freeze tactics.