The man who went shopping

Johnny wanted to buy shorts.He asked his mama for money.
" here," said she," but do spend it wisely.Remember, the salesmen are cheats,so you must bargain for your shorts."
Johnny goes into the shop and selects a colourful undie.He asks the salesman its price.
"Ten dollars !"
" How about five ?"
So they start haggling. At last the salesman agrees and wants a fiver. No says Johnny , Now I'll give two.
They haggle and the salesman is so irritated he says -take it for free." Then I'll take two."