How to barter or not

Bernadette: How much are the chairs?
Man: Twenty pounds.
Bernadette: would you do two for thirty?
Man: Sorry, no.
Bernadette: Go on. It's all I've got. Look...
(Pulls thirty pounds out of purse. An extra fiver flutters to the ground).
Bernadette looks at me with a question mark over her head.
Me: Give him the money.