Hotel Zone OXXO: Water bottle 45 pesos, bananas 40 pesos/kg, beer 35 pesos

Downtown Walmart: Water bottle 12 pesos, bananas 15 pesos/kg, beer 18 pesos

Daily savings shopping downtown: 150-200 pesos minimum. Weekly savings: 1000+ pesos. That's enough for 3 cenote tours.

Bus R1 to downtown Walmart costs 12 pesos each way. Even with transport you save massive money. Chedraui on Avenida Yaxchilán is closer but prices 20% higher than Walmart.

Bring a cooler or insulated bag. Hotel mini-fridges work fine for storing downtown groceries.