Amazon is rolling out a pair of hosted e-commerce payment services called Checkout and SimplePay for online retailers, joining a diverse market that most notably includes PayPal. The giant online retailer describes Checkout as a complete payment service that will allow merchants to incorporate Amazon's proven shopping-cart checkout system into their own sites.

Among its features is "one-click" functionality, as well as tools for managing shipping charges, sales tax, promotions, refunds, cancellations and chargebacks. Simply Pay, on the other hand, is basically a stripped-down version of the full Checkout package that doesn't include most of the order management features. However, it does allow sellers to provide more payment options and buyers to pay using information from their Amazon account.

Fees for both Simple pay and Checkout vary between 1.9% - 2.5% plus $0.30 per transaction, but payments under $10.00 incur a rate of 5% plus $0.05. Two years ago Google also introduced a rival service, called Google Checkout, but it has struggled to gain traction among web sellers. With Amazon being a recognized transaction expert, however, it will be interesting to see how many merchants start offering their payment services.