Free sex.

The owner of a gasoline station in Tattnall County, Georgia was trying to increase his sales, so he put up a billboard showing "FREE SEX WITH FILL-UP!"
Soon a local young man, Jim filled his tank, and then asked for his free sex.
The owner told him "pick a number froom 1 to 10; if you pick the right number, you will get your free sex." Jim picked the numner 8, and the gas station owner said, "You were close. The number was 7. Sorry, no sex this time."
A week later Jim, along with his buddy Bill, pulled into the station. Jim filled his gas tank, and again asked for his free sex. The station owner gave him the same story again, and asked him to guess a
number. This time, Jim guessed 2. The station owner said, "Sorry, the correct number was 3. You were close, but no free sex this time."
As they were driving away from the gasoline station, Jim said to Bill, "I think that game is rigged, and he doesn't really give away free sex."
Bill replied, "No it ain't rigged Jim. My wife won twice last week."