Actually they are pretty cheap, I paid around $20 for 2 of the 45mm and 2 of the 60mm delivered from Hong Kong. I think it was another $10 for the large bit.
The ones I have are unused and from what I've read you don't want to cut too many holes with them before the diamond coating wears off.
I don't want anything for the use. After you drill your hole or two just pass them on, but keep track of the # of holes cut w/each one.
You will need a drill larger than 3/8. I borrowed one from Jeff (Gath2) but forgot what size it was.