Cash, card, and the Pfand bottle deposit

Germany has caught up on card payments, but small bakeries, kiosks, market stalls, and some restaurants are still cash only, and "EC-Karte" signs mean they take German debit cards, not always foreign credit cards. Carry some euros. Bottles and cans carry a "Pfand" deposit of up to 25 cents, returned when you feed them into the machine at any supermarket, so don't throw them away. Sundays are quiet: nearly all shops are closed.