Virtualization provides increased control and flexibility in how resources are allocated to applications. However, common resource provisioning mechanisms do not fully use these advantages; either they provide limited support for applications demanding quality of service, or the resource allocation complexity is high. To address this problem we propose a novel resource management architecture for virtualized infrastructures based on a virtual economy. By limiting the coupling between the applications and the resource management, this architecture can support diverse types of applications and performance goals while ensuring an efficient resource usage. We validate its use through simple policies that scale the resource allocations of the applications vertically and horizontally to meet application performance goals.