This paper proposes an intelligent agent-mediated trading environment for business-to-consumer transactions. The generic architecture of the system enables it to be used with semi-structured product ontologies. The buying behavior model consists of the following fundamental trading agent-mediated stages: Product Brokering, Merchant Brokering and Negotiation Brokering. The Product and Merchant Brokering stages involve three agents: the Indexing Agent and the Retrieval Agent, that collaborate through machine learning, text classification techniques and fuzzy logic to match potential buyers with products and merchants, and the Profile Agent that creates the buyer?s profile using his/her relevance feedback. Finally, the Negotiation stage includes two transaction agents: the Buyer Negotiator Agent and the Merchant Negotiator Agent, that participate in an auction between the buyers and the ??suggested?? merchant acting according to the transaction strategies of the buyers and merchant respectively.