The penetration pricing strategy is intended to be temporary, such that once the desired market effect has occurred -- the penetration has been made -- the price is then put to a more "normal" price. An example of this in recent news is the introduction by Burger King of BK Smooth Roast Coffee. This new blend of coffee was developed to make Burger King more competitive in the fast food breakfast business, where it trails the market leaders badly. The new blend was offered with an introductory price of 25 cents (QSR Web.com, 2013). The objective of this pricing strategy was twofold. The first objective was penetration -- to get people to try the coffee in the hopes of winning over some converts. Ideally, the customer would come in daily during the promotion because this is the cheapest coffee around, and develop a habit.

The other objective...

So the pricing strategy was part penetration pricing for the new coffee and part loss leader for the breakfast business. If successful, Burger King would eventually raise the price of the coffee, having increased its market share with thousands of new habitual coffee drinkers visiting its restaurants.
Works Cited:

Clow, J. (2012). What small businesses can learn from Google. USA Today. Retrieved March 9, 2013 from http://usatoday30.usatoday.com/money/smallbusiness/story/2012-05-27/small-business-can-learn-from-google/55188670/1

QSR Web. (2013). Burger King celebrates new coffee with 25-cent promotion. QSR Web. Retrieve March 9, 2013 from http://www.qsrweb.com/article/208731/Burger-King-celebrates-new-coffee-with-25-cent-promotion