Without the performance characteristics for the fuse, I wouldn't imagine it would be cheap. Specialized electronic components are usually very expensive, especially if they're never mass produced and engineered to a specific task (component ICs for devices in space face the same issue). That engineering is pretty damn expensive, the tooling to make the small run of components is expensive, and quality control is expensive. Make a few hundred million and those costs vanish compared to the input materials, compared to a few thousand components where the overhead dominates.