In the Knowledge @ Wharton archives, I found an article describing an interesting controlled pricing experiment done by Wharton prof Marshall Fisher at the now-defunct Zany Brainy toy chain. Fisher and a colleague carefully chose store locations with similar profiles, which were located far enough apart that customers would be unlikely to visit both stores and compare prices. The researchers selected three products to test--a family board game, an educational traveling Phonics game, and a headset walkie-talkie--and tested each at three price points (in $5 increments). They found that while the family game and the Phonics traveler sold the most units at the lowest price, the walkie-talkie actually sold best at the middle price.
These results can be explained through several concepts from Kotler & Armstrong. Price elasticity (p. 355) is how sensitive demand for a product/service is to changes in price; a highly price elastic product would see reduced demand with any increase in price, whereas demand for a price inelastic product is largely unrelated to price. This relationship can be graphed on a demand curve (p. 354), which shows the number of units which will sell at different price points. Zany Brainy's family game and Phonics traveler would have a downward sloping curve, meaning that as the price went up, the demand went down. The walkie-talkie, on the other hand, actually had an upward sloping demand curve, indictating consumers' increased willingness to make the purchase as the price went up.
What might cause demand for the walkie-talkie to be greater at a higher price? The psychological pricing (p. 377) approach holds that consumers usually perceive higher-priced products as being of higher quality. This is especially true when the consumer cannot easily judge the quality on thier own, such as if they lack information or experience. In the case of the Zany Brainy experiment, the researchers theorized that shoppers were less dependent on price in their decisions about buying the family game (which is a straightforward item that customers were likely to know something about) and the Phonics game (which carried a name brand that consumers already had an impression of). The unknown-brand walkie-talkie, however, is a fairly complex electronic item which consumers were less likely to know how to judge on its own merits. Because of this, they depended on seeing the higher price as an indication that the product was of high quality.