Hi K.---Living in Michigan, I think Meijer has a better selection with the best prices. Shopping at Walmart is more of an ethics thing for me. I don't like their buying practices.
Having said that, as others have shared, I usually go to different stores for different things. Prices differ at even different Kroger stores. Selections are different as well. Take a little notebook with you, or make a list from your receipt and then take that with you for comparison each time you shop. You do have to take some time to check out unit prices as well. It's not always more economical to buy larger containers. And, be watchful of price increases. They do change and you might have to start purchasing certain items at a different store.
Lastly, be sure that you are not buying unhealthful food just because it's the cheapest. You diet is the single biggest investment in your health. If you trade dollars for health, you will realize that lack of investment as you age by increased risk of degenerative diseases. Even now, if you have allergies or get bad colds or flu, that is you immune system responding to a need for an optimal diet. Purchasing healthy food doesn't have to be expensive, it's actually more a matter of avoiding unhealthy food. Shop the perimeter of the grocery store. The fewer ingredients on a package, the better. If you can't pronounce it, don't get it. Do not get foods that have HFCS, MSG (goes by lots of different names-manufacturers hide it), artificial sweeteners or colors and all preservatives.
On a side note, K., would you be interested in attending a health education workshop next Tuesday, Sept 21 in Troy? If interested, let me know and I can send you a flyer. I would be happy to bring you a shopping list with healthy basics on it. Good luck with your best price exploration. Take care, D.