To make this thread of some substance, I'm going to digress considerably ;]
We are so inexorably drawn towards the word "free".
Out of the following options, which one would you choose?
* A $10 gift certificate for FREE!
* A $20 gift certificate costing $7.
If your first instinct is the same as absolutely everyone in a study carried out by Shampan'er and Ariely (2006) you'll take the first option, the free option. Economically, though, this doesn't make any sense. When you look at it you can see that the $20 gift certificate is actually better value: you actually get a $13 gift certificate for free, but this is camouflaged by the question. That word 'free' just shakes all rationality out of us.
Erm, some money psychology for you. Sorry. This thread just reminded me of it. Marketing sham >_<