Leaked documents from Staples suggest that Amazon may be entering the mobile-point-of-sale market and launching a card reader in the coming months.

The documents, obtained by 9to5Mac, show that Staples stores are preparing to stock a new product called the “Amazon Card Reader” alongside existing card reader products from Square, PayPal and its own in-house brand. The hardware, which will cost $9.99 (£5.88), will likely connect to smartphones to process card payments.

The launch date for the new product is unconfirmed, but the documents ask stores to wait until 12 August before putting up new signage related to the Amazon Card Reader, so the release is likely to occur sometime during that week.

Amazon launched a new Wallet app for smartphones last week, and the upcoming hardware is expected to connect with that software. In addition, there have been reports that Amazons hardware division, Lab126, is working on other mobile payment-related products, with a focus on using biometric fingerprint scanners.

Payment technology and software is rapidly becoming a new battleground for large technology companies, with rumours that Apple is also working on Touch ID fingerprint payment systems, and Facebook hiring David Marcus of PayPal to head its Messaging service, leading to speculation they will be adding a money transfer system.