The boy in front of her said he did. But he wanted something in return.
Girl: "What color do you want?"
Girl: "For that, I want three leads."
So, the girl pulled out a small fluffy pom-pom like purple ball and handed it to the boy. The boy handed her his case of leads. She pulled out a bunch, put back all but three, and returned the case to the boy.
Me: "What is that?"
Girl: "It was for a project. It's finished. These were extra."
Satisfied, I was about to move on...
Girl: "I would have given him one for nothing."
As he would have likely given her one lead for nothing. (A student running out of lead for a mechanical pencil and then asking around for a lead is commonplace. Just like asking for paper.)
But, in the end they both got something out of the exchange.
(It was funny how they both felt the need to explain to me how they were bartering, like they were doing something wrong. I was just entertained by how they worked the whole thing out between themselves.)