This paper presents a survey on several RFID authentication protocols under low cost restrictions. Low cost RFID are mainly addressed with limited security and privacy protections. In this study, we explore several protocols with various authentication mechanisms found in literature that satisfy low cost restrictions. Assessments of these protocols are based on data protection, tracking protection, forward security. Finally, it is concluded that no single low cost RFID protocol fully meets the requirement of the given assessments. While a protocol satisfies one or two assessments, it fails to fully meet the requirement of the third assessment. This study provides a new insight in RFID literature which can be used particularly by small and medium industries to choose the appropriate RFID protocol for their needs.