What would you do for a Mallowpuff?

Clearly a zerbert for a Mallowpuff is a pretty fair trade.

I'm certain Berkley wants in on this action.

A while later, Q told Jeremy that he would let him give him another zerbert in exchange for a Mallowpuff, which he couldn't say without giggling, by the way. They aren't dumb, are they?

edited to add: Thanks, Jeremy, he now thinks he can and should charge for zerberts.