Reconfigurable Intelligent Surface (RIS) is a promising technology that has received much attention for indoor localization in recent years. This technology can control the propagation environment by passively changing reflected signals. Many RIS-based systems need complex operations for the RIS configuration. Also, fingerprint-based indoor localization methods need several access points to create different fingerprints for nearby areas. In this paper, we present a fingerprint-based indoor localization system using RIS. We conFigure RIS, change its configuration repeatedly, and create a vector for each fingerprint. Simulation results demonstrate that the proposed approach can accurately localize users with a single access point. Moreover, it is shown that some parameters such as the number of reference points, the number of RIS elements, and the number of RIS configurations significantly affect localization accuracy. In contrast, the results are independent of RIS location.