This is a great talk by Rory Sutherland, the Vice Chairman of Ogilvy Group, about perceived value.

From the description on the TED page:

Advertising adds value to a product by changing our perception, rather than the product itself. Rory Sutherland makes the daring assertion that a change in perceived value can be just as satisfying as what we consider “real” value — and his conclusion has interesting consequences for how we look at life.