Groupon is launching Groupon Payments, a service designed to offer the lowest cost option for the company’s merchants to accept credit cards (view press release). Groupon Payments has been built into the latest version of the Groupon Merchants app for the iPhone and iPod Touch, providing restaurants and retail establishments and other businesses with the ability to accept all credit card payments. In addition, merchants can use the app to scan and redeem Groupons and monitor additional spend over the value of the Groupon.