I do Shaws (Albertson's) for the loss leaders, typically meat. Market Basket for general shopping, especially bread. Walmart for trail mix, TP, bacon. Hannafords for yogurt, other dairy. Cross the border into NH for non-price protected milk. The "app" is all in my head. Some people will see something and thing, gosh, that's expensive, must be inflation. Nah, it's the store messing with your head, listen to your cheap lizard brain and shop around.
No store will have a sale on spaghetti and sauce over the same week. Nor hamburger and buns. One needs a deep freeze and pantry space to really game the system.
Thanksgiving is when loss leaders typically go nuts, but this year may be weird. My $.69/lb turkey was $.79/lb!