The borrowed coin is on your business card.

This is an extremely effective way of introducing yourself as a magical performer.

You borrow a quarter of a dollar and take your business card.

Clap your business card with the hand having a coin in it.

The coins are already fused with your business card

and then you can give your business card away as a souvenir to the spectator.

This trick will make your business card unforgettable.