Knife

I never heard of that. I'm in the US, if it matters.

I was taught that giving a knife (or scissors) to a person would cut/end the friendship.

Therefore giving the person a penny with the knife allowed them to buy the knife from you and maintain the friendship.

I heard that you must give a penny for every point. 2 cents for scissors. 6 cents for a set of six steak knives. Etc.

Hey, the NRA sent me a genuine made in China pocket knife this month for renewing the membership. Am I good for having sent the check, or should I toss in another penny?

We always put a penny in a purse when giving one as a present.

Probably some old Anglo custom regarding cows, beans and giants.