What advice would you give a door-to-door fundraising teenager?

Hey Savages,

I just had the privilege to answer someone knocking at my door that wasn't a Jehova's witness..

I am guessing a 13-14 years old boy, selling chocolate within an organization that keeps teenagers out of trouble/out of the streets. 

Here is the context and a bit of our convo:

✊ ✊ Hi, Sorry to bother you sir. (nervous behaviour, eyes are barely making contact, speak very softly, clearly uncomfortable and inexperienced)I'm with X org that keeps teenagers off the street and we are selling chocolat. Here is my permit. (Behavior hasn't changed)

So I smile: ok great (I just want to help him at this point and the sales savage in me just want to give him a chance...). What'd you got?

X, Y and Z chocolat bar (digging in his front lunch bag/pouch), they are 2 for $10 or 4 for $20!

Me: Can I buy only one? 

Him (disappointed his tactic didn't work to upsell me): Yes 1 for 5$. 

I bought one for $5, and I didn't want chocolate. Maybe my wife will! 😎

Out of all you saw here, he you could give him ONE advice, in less than 10 seconds before he leaves, what would it be?

What I told him in the first comment below.