Directly targeting Apple’s growing iPad ecosystem with even lower-priced alternatives, Amazon today launched a series of three completely new Kindle devices with prices ranging from $79 to $199. The most basic Kindle e-reader will now sell for $79, a drop from the company’s prior $114 price tag for its lowest-end unit, relying on modest screen saver-style ad support and a streamlined design to reduce the price tag. Amazon also announced…