The first Tuesday of every month is Senior Discount Day at Walgreens. Their cashier will be happy to sign you up. Once your phone number is in the system, you will be given 20% off many of the items they offer.
The first Wednesday of every month is Senior Discount Day at Shopko. Same procedure: provide your phone number and you receive 15% off merchandise throughout the store.
The first Thursday of every month is Senior Discount Day at Safeway. If you have a Safeway card, just remind the cashier that you are a senior and you will get 10% off your grocery order.