Lucky Rock Part II

Tonigt Coop saw the rock he gave me (mentioned in last post) sitting on my night stand. He said, "Oh, that's your lucky rock, Mom."
Me: "Yep, because you gave it to me."
Coop: "I have another lucky rock (which he pronounces 'wok'). You can buy it from me."
Me: "Wow, I can? How much does it cost?"
Coop: "Three."
Me: "Three what?"
Coop: "Three costs." Pause. "That's not a lot of costs. It's a good price, not too expensive. It's a good deal."
I had to chuckle. Do I comparison shop enough, or what? Raising a little haggler.