The Clock Man by Shel Silverstein

“How much will you pay for an extra day?” The clock man asked the child.

“Not one penny,” the answer came.

“For my days are as many as my smiles.”

“How much will you pay for an extra day?” He asked when the child was grown.

“Maybe a dollar or maybe less, for I’ve plenty of days of my own.”

“How much will you pay for an extra day?” He asked when the time came to die.

“All of the pearls in all of the seas, and all of the stars in the sky.”