In this study, we present a technical and economic assessment of high-current HTS bus bars for primary use in fusion reactors. Our objective is to verify the technical feasibility of such conductors and, for this purpose, we carry out a conceptual design of 66 and 105 kA DC bus bars, e.g. as a potential solution for powering the European DEMO power plant. We employ commercial HTS tapes and reasonable (as well as conservative) assumptions on cooling configurations and costs. Then, we compute the material, manufacturing and operating costs of these bus bars, comparing them with conventional (i.e. Al) conductors. Different Al current densities are considered, showing their impact on the total costs and on their technical feasibility. The cumulative operating costs over a 30-year period, based on nowadays realistic values for electricity cost and discount rate, are then briefly compared and discussed. We believe the present work could be of interest in designing the power supply system of future fusion reactors and other high-current industrial applications.