The 3rd class lever that I found was a stapler.
The formula for a lever is
You apply the force three inches from the fulcrum and the force is applied to the staple five inches from the fulcrum, so the Ideal Mechanical Advantage is
So for every pound of force I put on the lever, the lever applies .6 lb. It also means that for every inch I push down, the staple is pushed inches. So I am sacrificing force in order to staple faster.