Collaborative e-learning virtual communities use virtual learning environments provided by the university or tools that are available in Internet. Although this model has proven to work, it has limitations for adhoc and peer-topeer groups due to the dynamic nature of its resources. A way to deal with it is by defining virtual organizations (VO) that gather the resources and interests of their members in a way that they can lend resources to or borrow them from other VO. This paper presents DyMRA, a decentralized resource allocation system based on markets that allows inter-VO resource allocation. DyMRA is specially designed for collaborative peer-to-peer environments, where the autonomy of participants and its decentralized nature requires the capacity to dynamically reallocate resources and services that manage the overall system. DyMRA is built on top of LaCOLLA, a peer-to-peer middleware that allows a group of users to share resources in a collaborative manner. We present the design, architecture and validation of our proposal.