Lemonade.
or
1,000,001: One to change the bulb and 1,000,000 to rebuild civilization to the point where they need light bulbs again.
or
Fish and ships.
or
First they have to agree on which is better; the analog bulb or a digital bulb.
or
A bad lawyer makes your case drag on for years. A good lawyer makes it last even longer.
or
Silverware.
or