One of the advantages of implementing Amazon Flexible Payments for digital goods transactions is that the workflow is basically the same for physical or digital goods. Using the FPS Co-Branded UI, your customers submit their payment to the Amazon processor and are returned to a URL that was specified when the transaction started. In the case of physical goods, this is usually a receipt or thank you page. For digital goods, we would serve up the media download right away. Flexible Payment Services was discussed in Chapter 4, From Payment to Porch: An Order Pipeline.
Amazon offers another API, however, that may be of interest to digital content merchants. The FPS Aggregated Payments API is designed to aggregate many small transactions into a single, combined transaction. This has many advantages, but the most important is to reduce transaction charges.
An aggregated payment system is designed for applications that sell many different products to the same customer...