I am having difficulty understanding how the Avignon Pass works.

I understand it is free, but I am not sure how the discounts work. It says use it in one place and the second one is half-price. Does that mean:

All subsequent places are half-price?
Every other place is half-price...2nd, 4th, 6th, etc.?
Only the second place is half-price...subsequent places are all full-price?

The website says: "1st visit: full price. As of the 2nd visit: PASS price. ", which leads me to thinks option 1 is correct...but it sounds too good to be true.

Thanks.

ssander