Bob wanted to board his horse.
The first farmer he asked said he would keep it at $25 a day, plus he would keep the manure.
Bob thought that was too high and went to another farmer. His price was $20 per day plus he would get to keep the manure.
Then he went to Joe who asked just $5 a day.
Bob asked, “Don’t you want to keep the manure?”
Joe said, “At $5 a day, there won’t be any!”