Where can I find Monster^® in Walter's Ash?

Monster can also be found in these cities:

Amersham Aylesbury Chalfont Saint Giles Chalfont Saint Peter Great Missenden Hemel Hempstead High Wycombe Iver Loudwater Maidenhead Rickmansworth Slough Sonning Common Stoke Poges Tring Wooburn Green Woodcote invalidcity

You can also find this in Walter's Ash:

Vegetables Fruit Snacks Frozen Food Eggs Soft Drinks Confectionery Soft Drinks Cheese Cider