Groupon has decided to launch their mobile payment system, Groupon Payments, across the United States after a successful pilot program for Groupon in the San Francisco Bay Area earlier this year. Groupon Payments is baked into the latest version of the Groupon Merchants application for the iPhone and iPod touch, and will let merchants run credit card payments as well as the ability to scan and redeem Groupons.

Groupon have specific rates for swiped transactions using the required audio jack accessory, or the case-based reader. MasterCard, Visa and Discover all get slapped with 1.8% plus a $0.15 fee per transaction. American Express, as usual, is more expensive at 3% plus the same $0.15 per transaction fee.

The company have stated that there are no hidden costs, or monthly fees, and that merchants will have their credit card payments deposited into their bank accounts overnight, versus the competitions way of making them wait it out for a few days. In order to lock in the low transaction rates, merchants will need to run deals with Groupon, which is a bit of a hassle.