Buy a deck of cards.
or
One. No, two. No... How many do we have on the truck?
or
A porcupine with split ends
or
Only one, but she/he'll have to go out and buy the light bulb adaptor card first, which is extra.
or
Two: One to screw you out of a fee, and the other to send you to a store where they ran out of bulbs weeks ago.
or