The "greenlights" site sells only the buttons, not the LEDs and PCB etc.. and Chris will likely ship them via airmail, which keeps the cost rather reasonable.

As for the LEDs and stuff -- they're not cheap over here (Canada) -- the major source we have for them is Digikey.ca, where they cost about $2.50 each.. which adds up.

And a custom low-run PCB can be rather expensive to produce in tiny quantities, thus the higher cost of that item too.

I don't think there's anything here to suggest that these items are overpriced at all. Expensive, perhaps, but that's what they're costing the seller as well.

Cheers