Hi Zak,
I don't know if you've gotten any responses but if not the reason is that even though the machining looks straight forward, without dimensions it's hard to even estimate material costs.
If you have gotten responses then I'm not being nearly as helpful as I think :)
Thats personally what I would guess. The price to have a new key made/cut by the dealer can range from $100 to $600 and in some cases take 6-8 weeks to arrive from overseas.
There are also way easier ways to steal a car then trying to cut a key for it, although I wish more thieves would use...