Nachfüllen gratis

I found a place with free refills in Aachen today. It's a Subway. The McDonalds I've tried so far haven't had them, so I'm glad to have found this Subway. And I finally figured out what to call it, since I have thought for a month and asked multiple people and come up with no good answer. Free Refills in German is "Nachfüllen gratis." So now you know what to ask for. Speaking of free refills, there's a Pizza Hut in the center of town with all you can eat that I'll try out one of these weeks.