In China they sometimes sell coffee in such a way that you can buy two cups of coffee, but you can collect only the first one today, and the other one at any other day starting from tomorrow. You would have to pay for both cups today - the full price for the fist cup and only 50% of that for the other cup. On the day when you make this purchase, they will give you a special ticket that will allow you to pick up your second cup (without paying, of course) starting from the next day.
I wonder how this format of selling is called in English. In Chinese they call it simply "one cup, another cup". So a sentence like "I want to buy one-cup-another-cup coffee, please" is quite common. But how would a native English speaker express the same thought in English? Is there any special term for this kind of selling format?