Blockchain technology implementation is becoming an increasing trend in supply chain operations around the globe. However, the blockchain costs and its impact on the supply chain operational outcomes are still unclear in the literature. Specially, online retail (e-tailer) supply chains can derive significant benefits from blockchain implementation, as they heavily rely on accurate information and proper information sharing among the supply chain members, who are located distantly and externally. The rapid sales growth in the e-tailer supply chains further reinforces the importance of identifying the costs of implementing a blockchain system to derive insights for strategic decisions to improve the operational effectiveness of these supply chains. Therefore, we investigate the cost determinants of public and consortium blockchains in an operational framework of the e-tailer supply chain. The findings emphasize that the transaction fee is a determining factor, and the public blockchain operations are costly in long term operations than the consortium blockchain operations.