One selfie per yard

Walking to a fabric store counter, the pretty girl said, “How much does this fabric cost?”
“Only one selfie per yard,” replied the clerk with a smile on his face.
“That’s fine,” said the girl. ”I’ll take 15 yards.”
The clerk measured it and wrapped the fabric and took out his phone.
The pretty girl snapped the package and pointed to the old man behind her, and smiled,” Grandpa’s gonna pay the bills.”