It looks like Amazon is about to release another piece of hardware. After over a year murmurs, documentation from Staples internal inventory system suggests that Amazon is almost ready to unveil its own point-of-sale system to compete with the likes of Square and PayPal Here. A copy of the inventory documentation provided to 9 to 5 Mac includes an unreleased product referred to as an Amazon Card Reader. The site reports that its marked as a $9.99 product and the system notes that signage related to the reader should be held until August 12th. In that report, the paper said that Amazon was working on a point-of-sale system similar to the Square reader.