The provisioning of remote and composed services in support of various application areas has dramatically increased over recent times. Thus, the concept of Grids has evolved, in the sense of a common platform for electronic service provisioning in multi-domain environments. While, traditionally, Grids have seen a quite static existence, many new service compositions have to take place on-demand and for certain periods of time only. To tackle those issues the concept of Virtual Organizations (VO) delivers a highly suitable representation of such dynamic Grids. However, one important open problem at this stage is the lack of applicable, distributed, and efficient accounting schemes for commercial resource and service consumptions. Even for simple management purposes, e.g., sampling or archiving, this functionality is essential.Therefore, a comprehensive model for Grid accounting has been developed and suitable accountable units have been defined, in which an underlying activity-and resource-based accounting model covers economic cost theory. Furthermore, this work is based on a service model proposed for service provisioning in dynamic VOs, overcoming the typically static nature of traditional Grids.