$79 is a great price point! It will help bring Kindle to masses (and will speed up the death of the printing industry
).
However, make sure you understand the limitations of this entry-level Kindle, before you buy one.
It's not just the ads, but also, the twice smaller memory size, the twice shorter battery life (compared to other new Kindle models), the absence of the keyboard (physical or touch-screen), no 3G option, no audio support at all, not even an audio jack! And keep in mind the cost of the accessories: there is no power supply included, and the case is rather expensive - those things can almost double the price of the unit, if you need them.
It's a good basic e-reader, but the slightly higher priced new Kindle Touch might actually be a better deal overall!