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
Shamboo!
Frankenstein: Witch can you make me a lemonade?
Witch: Poof you are a lemonade!
or
Just one, but he/she will spend hours checking for technical problems.
or
It's not a shrub, it's a lemon tree my dear Watson.
or