Virtual collaboration is an important aspect for the success of scientific projects, especially if participating researchers are distributed over the whole globe. In the recent past some systems - so called virtual research environments - were presented to support collaborative work restricted to certain research domains. Within this article a concept of a generic framework for building personal, cloud-based virtual research environments easily is proposed. Such an environment could be defined by composing arbitrary services, appropriate to the requirements of a particular scientist. Due to low funds in some scientific areas, we also provide a flexible billing strategy using the cloud specific pay-per-use model. Thus, each service has just to be paid as long as it is utilized. Virtual Research Environment; Cloud Computing; Layered Architecture; Virtualization; Virtual Collaboration; Pay-per-use I. INTRODUCTION