Well, it is public bathrooms you have to pay for here, as they are run commercially. But each place that offers food or drink and where you can sit down (so e.g. a food vendor cart is excempt) has to have free toilets for their customers. Some might be better, some might be worse (I've been in a McD in a ... not so well off part of a town and it was horrible - you had to ask for a key, and they had this horrible, dim bluish light that is supposed to reduce drug use). But customers toilets are free.

A friend of ours had a restaurant at a hiking trail in a forest, and he had put up a donation box for those who just wanted to use a toilet without eating or drinking there, which I consider fair.