Way to go Lisa! It's not worth wasting time with people like that.
I think small businesses really need to be careful and not give in to these demands for lower prices. There are too many people out there that will try and take advantage of small businesses in this way. If they don't like the prices, they can go shop somewhere else so you can devote your time to your real customers.
And by the way Lisa, you still haven't hung up on a customer yet. She wasn't a customer - she was just a rude lady that didn't buy anything.