Currently, we can observe the growing of the use of mobile devices as a media for both Internet access and carrying out purchase and sale of products and services. Commonly, E- commerce platforms are enabled by either proprietary systems or by buying ads on specialized websites. This scenario involves the adoption of strategies based on e-commerce servers, which represent a non-scalable strategy. The situation is even more critical considering the current scenario, where mobile devices has been involved in trading, the so-called m-commerce. In this context, this paper proposes the use of the P2P technology as the network substrate for supporting mobile commerce. For that, we are using the notion of ultrapeers that act as managers that receive, process and pass on requests for trade. Suppliers and consumers act as end points and access ultrapeers of their geographic region through a standardized interface. To implement the distributed scenario, changes are made over the DNS servers so that mobile devices can locate ultrapeers based on their geolocation data. Thus, suppliers who need to travel can advertise their products in the regions which they pass, boosting their business through this opportunistic approach. Finally, experimental evaluation showed that the architecture is feasible for mobile commerce environments composed by both stationary and mobile devices.