A common business practice, especially at fast food restaurants or grocery stores. Buy one item, and get a second of equal or lesser value. The customer is happy, and comes back and spends more money. At least in theory.
A pizza place near my dorm has one of these deals. In fact, it is impossible to get just one pizza from them; they will make you get two. Has reportedly led to many humorous phone conversations by freshmen over the years, who cannot figure out why the pizza place keeps asking them for the topping to the second pizza when they only want one.