Sony has given a nod to this user niche by naming the model the Daily Edition. The Reader will use the AT&T wireless network in the US to grab content and will go on sale in the US in December.
No European launch date has been revealed.
It follows on from the launch earlier this month of the Reader Pocket Edition and the Reader Touch Edition, which has a touch screen. Neither has 3G capability and both of these models are cheaper than Amazon's Kindle at $199.
However, the Daily Edition is priced at $399, making it $100 more than Kindle, which also has wireless capability and is yet to be launched in Europe.
Sony is pushing its Reader brand by opening it up to various publishing formats, meaning users can download books and other content from the Sony eBook store and other sources, including some libraries. Kindle users are mostly limited to e-books available on Amazon.
But while Sony is set on challenging Amazon, another rival is likely to emerge shortly, with details being leaked of Apple's "tablet" reading device.
Previous launches, such as the iPhone and the iTouch, have proven that fans of Apple's elegant designs are often willing to overlook certain flaws or limitations of the technology, and its release is likely to give a major boost to the uptake of e-readers.
Steve Haber, president of Sony's digital reading business division, said: "We firmly believe consumers should have choice in every aspect of their digital reading experience. Today, we take another large stride to deliver on that promise.
"We now have the most affordable devices on the market, the greatest access to free and affordable eBooks through The eBook Store from Sony and our affiliated ecosystem, and now round out our Reader offering with a wireless device that lets consumers purchase and download content on the go."