This is ingenious! I am trying to replicate the removable blade, and am considering using bike brakes, but that's all I've got. I don't suppose you'll consider explaining the mechanics of the removable blade part?
I am going to either use water transfer film or sanded airbrush paint to create a brushed steel effect. As for the steel, it would probably be cheaper, but I would imagine that much of the detail would be lost (unless it was made up of multiple layers and assembled like a LOM 3D print).
I did print this with my own printer, so I am not sure how much it would cost to print through a printing service. However, your cost estimate is probably right; I could easily see this costing over 80 EUR.