Spare change?

It's tough.  Wanting something so badly but then realizing that you just can't have it.

With a twenty and a five in her wallet and a $37 blouse on her back, Juliana thought that she might have enough change in her purse to make up the $12 difference.

So she dumped her money out and counted it.

On the change room floor.

I wonder if that's why it's called a 'change room'?