Also, if a common jet figher costs $90m per unit, it wouldn't surprise me an unmanned, remote-control drone costs significantly more per unit.
I don't see why it should cost more, once R&D is no longer a factor. It's just metal and electronics. I can buy a small drone for £100. Probably, I didn't actually check that. But I know people with drones, and they're not exactly wealthy folk. I appreciate a military grade drone with weapons is going to cost a ridiculous amount more than a shitty drone with a GoPro attached to it, but compared to a plane, it should be a similar amount of material.