Walmart has a reputation for selling things before the street date. In fact, we just saw this happen a few weeks ago with the Xiaomi Mi Box. This time, it's Google Home that has (I'm sure completely by accident) made its way to the shelves of at least one Walmart.
Google Home is not supposed to be out until November 4th, so Walmart is the better part of a week early. Many other retailers have them in stock, but have not put them on shelves yet. It's priced at the standard $129, but our tipster reports that Walmart reps would not sell him the device. You might have more luck if you check out your local store—maybe there will be a less well-informed employee.
Google Home will be the second device to feature the full implementation of Google Assistant. You'll be able to use it to access data from the web, as well as your own personal data. There will also be tie-ins with various smart home platforms like Nest and SmartThings. All that, and all you need is your voice.