I was shopping at a shoe store recently for a new pair of dress shoes, and finally found what I was looking for and brought my purchase to a counter. "Don't you know about our 2-for-1 deal?" the woman at the counter asked me. "With this purchase, you could buy a second pair of shoes for only $5 more."
I mulled it over and realized that I really had no need for a second pair of shoes. The temptation was there, for sure - what a deal! But I've been actively trying to reduce the clutter in my home, and I really needed only a replacement pair of shoes - not to augment my otherwise-sufficient collection.
Many two-for-1 deals get you an extra set of something that you don't really need. But I've been surprised to discover recently that, despite a great deal of effort to describe our product (bolstered by Symantec's powerful marketing machine), many of our customers don't realize that NetBackup for VMware even has a 2-for-1 deal going.