"Very Cheap" joke

After being away on business, Tom thought it would be nice to
bring his wife a little gift.
"How about some perfume?" he asked the cosmetics clerk.
She showed him a bottle costing $50. 00.
"That's a bit much," said Tom, so she returned with a smaller
bottle for $30. 00.
"That's still quite a bit," Tom groused.
Growing annoyed, the clerk brought out a tiny $15. 00 bottle.
"What I mean," said Tom, "is I'd like to see something really
cheap."
So the clerk handed him a mirror.