Pricing and charging are important management functions which future commercial networks will have to offer. Since the Internet is on the move to provide differentiated services, suitable and scalable management mechanisms are required for the backbone based on the Differentiated Services (DiffServ) Architecture. Since network management following actual market forces has to implement a price-driven and charge-driven approach for managing the usage of services, this paper introduces as a first contribution the design of a generic and modular Internet Charging System (ICS), offering a service-independent architecture and integrating economically controlled network management functions into present Internet technology. Moreover, a central part of this ICS, i.e., the Internet Charge Calculation and Accounting System (ICCAS), is presented in more detail and offers necessary user support functions. The second main contribution of the paper focuses on the newly developed Cumulus Pricing Scheme (CPS). CPS is unique to define clear relations between different time-scales for accounting, monitoring, and charging activities. Charges in this schemes are based on flat fees and, hence, are predictable and transparent, whereas, unlike pure flat rate schemes, the incorporated feedback mechanism nevertheless allows to take market forces into account. Finally, it is demonstrated how the ICCAS is well-suited to integrate both DiffServ technology and CPS.