Case in point: Subway has what seems like a great promotion running. $5 footlongs. Sounds nice, doesn't it? At Subway though, the Double Stacked 6" sandwiches have just as much meaty goodness as the footlongs. So check this:
6" Double Chicken Teriyaki: 480 calories, 7g fat, 100mg Cholesterol, 65g carbs
Footlong Chicken Teriyaki: 750 calories, 10g fat, 100mg Cholesterol, 118g carbs
And they cost the same. $4.38 here for the double, ~$5 for the promotional footlong. I'm sure it is even worse because I use the Italian Herb and Cheese bread rather than the regular Wheat or Italian.
Don't be fooled!