Not Worth it_英语成人笑话

an egyptian man is walking through the cairo bazaar, when a stranger comes up to him and offers to sell viagra (illegal in egypt) for 100 egyptian pounds.
"no, not worth it!"
"ok, how about 50 egyptian pounds?"
"no, not worth it!"
"ok, 20?"
"no, not worth it!"
"how about 10?"
"no, not worth it!"
"listen, these pills cost us $10 each. how can you say they are not worth it?"
"oh, the pills are worth it. my wife is not worth it."