1: None of your business, huu-mahn !!!

2: Depends. How much?

3: Two: one to change it, and the other to sell the old bulb as an antique.

4: Two: one to change it and one to sell the old one as new

5: None: they'll just sell the whole lamp to some young Starfleet Ensign.

6: Just one, but he'll charge you double for it.

7: Ferengi Never change!!

8: For the right price, as many as you want.

9: None...they steal it and sell it for profit

10: Two. one to steal a new one, the other to go sell the broken one.