Derek Landy said this quote

No one likes sarcasm, Miss Cain. I’ve merely delayed my exit to promise you something. You took my straight razor, li’l darlin’. That I view as an unforgivable offense. So when the time comes, when you have served your purpose, I swear to you I’m gonna kill you for free.” And with that, Billy-Ray Sanguine disappeared into the ground. Then he popped his head back up. “Or at least half price.” And he was gone again.