This paper presents a low-cost social robot, called Philos, and human-robot interaction (HRI) design. The system is accompanied with a user interface that allows customization of interactive functions and real-time monitoring. The robot features eight degrees of freedom that can generate various gestures and facial expressions. HRI is realized by two elements, internal characteristics of the robot and external vision/touch inputs provided by the users. Internal characteristics determine the predefined personality of Philos among the five: Friendly, Hyperactive, Shy, Cold, or Sensitive, and set the behavioral control parameters accordingly. Vision-based interaction includes face tracking, face recognition, and motion tracking. Embedded touch sensors detect physical touch-based interaction. Behavioral parameters are updated in real time based on the user inputs, and therefore Philos can engage each user in personalized interaction via uniquely defined behavioral responses. The cost of Philos is estimated to be relatively low compared to other commercially available robots promising a broad range of potential applications for domestic and professional use.