In recent years, with the use of e-commerce sites the need for adaptive contents to help customers to find suitable online products to purchase. Despite the limited use of adaptive services, most of these sites have “complex buyer behavior” often marked by customer confusion and information overload because of neglecting customers purchasing power ability. Therefore, this paper applies psychological testing method called Computerized Adaptive Testing (CAT) taking into account product price, quality and customer ability (customer purchasing power). Whereas, the proposed system focuses on a new adaptivemechanism that gives the customer an opportunity to select best products from several categories on the basis of consumer perceptions (e.g. perceivedquality and perceivedprice). Experiment results show that applying CAT to E-Commerce can help and enhance buying decision process when searching for and selecting online products by providing suitable product quality and price with corresponding customer’s ability.