Free Sex With Fill-up

Instapundit links to this piece and this one. Both ignore the story Lewis Grizzard told on Designing Women :

Bubba and Earl are driving back to Athens from Atlanta when they notice they need some gas. They start looking for a gas station and see a sign that reads "Free Sex with Fill-up." They pull in and tell the attendant to "fill 'er up." After he's done the attendant goes to the window and says that it would be $18.00 for the gas. (This is an old story.)

They pay and as the attendant starts to walk away Bubba yells "What about my free sex?". The attendant rolls his eyes and goes to the window and says, "OK, but you have to guess the magic number. It's a number between 1 and 10." Bubba said, "6." The attendant says "No, the number is 3. Sorry."

As the attendant starts to walk off Earl says, "Give me a try." The attendant says "OK." Earl says, "7." And the attendant says "No, I told you the number was 3."

Bubba then speeds off and Earl looks over and says, "I think that game was fixed. There is no way to win." To which Bubba replies, "Uh, Uh, my sister won three times last week."