From a manufacturing standpoint these look pretty simple and low cost to have made up from a factory in China and shipped out from there. Definitely under $10 for the kit of two including shipping costs and packaging. Looks like Asus isn't expecting to sell too many which is where the high price comes in - they probably needed to order 10k of them to get them made.
I'd expect to see these on clearance for $7.49 per kit in a few years time. Even at that price they haven't exactly lost their shirt on it.