Amy Daczyzyn reader from way back here.
Don't overthink it, just sit down with your most recent grocery receipt and a pocket sized notebook and make a pricebook.
Top of page 1 write Eggs. Create columns for stores in your vicinity.
Rows will be dates you shopped. In the cell/square, fill in price you paid. Circle it. Then take the notebook with you on the next trip to the store. In the store, plop in prices as you see things. Circle if you actually bought it.....this is how I know Aldi has best prices on eggs, all the time. It's how I know Shoprite will have a sale on butter at specific intervals. It's how I know how old my olive oil is and what I'm wasting if the big jug gets rancid and wipes out any hope of savings by getting the lowest shelf price per ounce.
I make my living in technology, but prefer a low tech approach here. The big data version of what you describe is already done by the USDA to help set SNAP and farm subsidy rates. It is also globally tracked here:
https://www.numbeo.com/food-prices/country_result.jsp?country=United+States. But big data metrics don't tell you when your farmer's market has patty pan squash by the truckload and hence almost free or the difference between bread worth eating and bread that is an abomination.
My little notebook is a grocery list to share between the two of us, and it's customized to the things we actually eat & use and the stores where we can shop.
What my pricebook proved to me is what we saved replacing most of the meat in our diets. It shows that we actually don't save by buying in bulk. Since the sales come around regularly, I don't have to buy next month's chicken today and risk spoilage or waste in my own home. I keep the money and let Shoprite or Aldi supply the refrigeration until the week I'll be eating it.
Amy's method involved research trips to scout out best prices, and only you can determine if that is a step you'll deem worth taking. I just dove in with a receipt.