We consider negotiation over resources among self-motivated agents. Negotiation occurs over time: there are time constraints that affect how each agent values the resource. The agents also consider the possibility that they will encounter each other in future negotiations. We cope with agents having incomplete information, emphasizing probability management techniques. Questions arising in this research are: 1. When is it worth it for an agent to lie? 2. How beneficial can such lies be? 3. Is the system with a lying agent robust? 4. How can lies be discouraged? The main contributions of this work are our ability to deal with multiple encounters among agents, and our treatment of the problem that enables elementary mutual learning.