The video below is from July, though I only discovered this version recently. I had always seen one titled "Atheists Bitchslap" that ended after the woman, Kate Smurthwaite, said, "...I'm not an idiot." It was harsh, but a point with which I agree - it's not smart to believe in things without evidence. However, this extended clip shows the theists proving her point by claiming that she has faith that money exists. That's just a load of bull, and she gives some examples of why that is.
I think I understand where they are coming from, though. Money symbolically represents something else that has value. Money is essentially the solution to an overly complex barter system. By that I mean to ask what do you do if person A has something that person B wants, person B has something person C wants, person C has something person D wants, and finally person D has something person A wants? You can't necessarily get all four people together to exchange items, so you instead create something, money, that represents the value of the items. Nowadays, with computers, the exchange of money has even become symbolic. So you have symbology on top of symbology which creates an even greater disconnect from the physical objects that are represented. At some level, they know this, and I think the best response that I saw that would reveal this would be to ask them for some large amount of their nonexistent money. After all, if it doesn't exist, that shouldn't be an issue.