In recent years electronic commerce has grown rapidly as Internet and web technologies have progressed. Therefore, a secure and efficient payment system for general-purpose applications is undoubtedly becoming an important issue. Rivest and Shamir have proposed a micro-payment scheme which is user-specific and vendor-specific. However, in their scheme, it is required that the user generates a new payword chain for each vendor from which the user makes a purchase. In this paper, we propose a new micro-payment system that enables users to make purchases from multiple vendors. Only one payword chain has to be generated which makes this system very efficient. A sequence of payword chains which represents a set of small payments can be authenticated and payment can be made by an efficient method. A lower computation cost and improved system performance is also achieved. Therefore, the new micro-payment system has multiple practical applications.