I didn't see how much paid for the course instruction, so I can't comment on whether its ridiculous to pay for the c-card on top of it.
While the LDS I work for bundles everything in, I prefer to list the separate costs when teaching independently. I prefer not to get into the course materials sales end of things. I point my students to my LDS, but if they want and can but it cheaper from someone else, more power to them. I try to avoid having to track 'product' sales for sales tax tracking reasons. Also, I often get asked, how much if I already have gear, how much if I do the training in their pool, how much if I already have the book, etc...
Since its all listed, they can see for themselves AND it shows how much I charge for my instructional time (vs. other participants in the value chain).
That being said, I don't markup other's fees and yes, 40 euros seems quite high.