The truth is, as they say, in the fine print. This sentiment is no truer than in the world of mobile phones. Plenty is written about the price of handsets, but - especially in the U.S. - that price is nearly always followed by an asterisk. If you want the subsidized price, you're going to have to sign a two-year contract with the phone's wireless carrier.
A few years ago the concept of a "smartphone" was virtually unheard of. There were a few phones on the market performing some interesting technological tricks, one that springs immediately to mind is the Palm Trio. Basically, a Palm Pilot capable of performing a few phone functions.