It is common in the buying decision process for a product, that buyers consider the characteristics of competing brands, too. Similarities between products of competing brands, make it hard to choose a certain product based merely on a common product-related feature, such as product price, special characteristic, quality and reliability, as well as financial commitments provided by the producer and so on. In this situation, in addition to the sales agents, the warranty, spare parts availability, preparation fees and maintenance and repair services are involved in choosing the product. There is no doubt about the role of warranty in customer satisfaction, increased sales and flexibility against customer requirements. Many products are offered with a variety of warranties, which among them, cost sharing warranties, failure modeling during the warranty period and the cost of this policy are encompassed by a lot of complexities; Because the cost of product correction is a random variable, also affected by interest rates and inflation.