Kindle Wi-Fi launches

The Amazon Kindle Wi-Fi e-book reader is shown. Amazon.com launched a cheaper, wireless-only Kindle on Wednesday, betting that the US$139 price will turn its latest electronic reader into a mass-appeal device as Apple Inc's iPad gains ground. The world's largest online retailer and leading e-reader seller also revealed its third generation Kindle, some 21 percent smaller and 15 percent lighter than the previous version, but still priced at US$189.