Image-based visual gaze estimation has been widely used in various scientific and application-oriented disciplines. However, the high cost and tedious calibration procedure impede its generalization in real scenarios. In this paper, we develop a low cost yet effective webcam based visual gaze estimation system. Different from previous works, we aim at minimizing the system cost, and at the same time, making the system more flexible and feasible to users. More specifically, only a single ordinary webcam is used in our system. Meanwhile, we also proposed a novel calibration mechanism which takes account binocular feature vectors simultaneously, and uses only four visual target points. We compare our system with the state of the art webcam based visual gaze estimation methods. Experimental results demonstrate that our system can achieve satisfactory performance without the requirements of dedicated hardware or tedious calibration procedure. © Springer International Publishing Switzerland 2015.