The point of the original experiment was to have the charges be near-zero but tiered with respect to the other items available. It could easily be adapted to a

The point of the original experiment was to have the charges be near-zero but tiered with respect to the other items available. It could easily be adapted to another country and currency. And it wasn't a buy as many as you want thing, it was a one-time-only deal offered in the checkout line. So, it's not about multiplying zero. It's about a single instance. Free breaks the logic of most people.