"On The Cheap" joke

Edgar decided that an appropriate Christmas gift for his wife would be a bottle of perfume.. Nothing too expensive or overstated mind, just something simple and discrete.
So he went to a local store and located the cosmetics department.
"I would like to buy some perfume for my wife." he told the shop assistant.
"Certainly sir." she replied. "Do you have anything particular in mind?"
"Not really." he said "but nothing very expensive."
"I understand sir. Well, what about this one?"
"How much does it cost?"
"This one is sixty pounds sir
"That's too expensive for me." he replied immediately.
"Very well sir. How about this?"
"What's the price? he asked.
"Forty pounds sir."
"What else have you got?" he enquired.
"Well, there's this small bottle at twenty pounds."
"Look here." he replied, "what I'm really looking for is some really cheap."
The shop assistant looked Edgar straight in the eyes, picked up a mirror from the counter and held it up to his face and said.
"This is as cheap as you can get sir."