I've had a NSF cheque once. I charge $30 if this happens and my bank charges me $15 so technically I make an extra $15 for this inconvenience. This parent did this once and never again.

I had another parent put a stop on a cheque and again, I was charged $15. She paid me in cash the same day she stopped the cheque (she had an issue with Visa taking out too much money and she knew this so she paid me cash). I only charged her the $15 that my bank charged me.