Horse Keeping......

A lady wanted to board her horse. The first farmer she asked said he would keep it at $25 a day, plus he would keep the manure.
She 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 she went to a third farmer who asked just $5 a day.
The lady asked, "Don't you want to keep the manure?"
The farmer said, "At $5 a day, there won't be any!"