With its combination of online and face-to-face interaction, blended learning is increasingly being employed in postgraduate education. To date, most empirical research on the topic has focused on the design and relative effectiveness of online versus in-person learning. Meanwhile, any exploration of the costs of its delivery has often been neglected. In this study, we propose a framework to assess the costs and cost-effectiveness of alternative designs of blended postgraduate programs, and then empirically apply it to an innovative blended Master of Business Administration (MBA) course as compared with similar MBAs taught at the same institution, with the differences lying in their proportions of online content and the intensity of their use. We applied the Community of Inquiry framework to show that the program with the most intensive use of online learning is also the most effective in terms of student cognitive gain. However, it is not the most cost-effective when compared to other, less online-intensive alternatives. We also found that this result depends on the scalability constraints imposed by the design of the programs. The implications of the scalability versus the quality versus the costs of blended education are then discussed.