Would you do that? Very often others would ask me how much is a kg of meat etc cost and seriously, after turning into a housewife for about six years now and I had never memorized those prices. I would go to the market every weekend and buy what ever I felt like eating that week and shop till I am out of cash and I would go home. During the week I would cook what ever I could find in my fridge. So I do not really compare prices nor know how much it really cost per kg.
I go by how much I am willing to spend on food for that week and not going round town shopping for the cheapest meat, vegetables etc. I have neighbors who would buy chicken from market "A", fish from market "B" and fruits and vegetables from market "C". If the three markets are quite a distant from each other, the fuel going there would have cost more than buying everything from one place.
You could say I am the lazy type but to me I wouldn't want to stress out on a simple task like marketing for food for the family. Why go through the hassle comparing prices, taking notes and keeping an eye on food prices like watching the share market on CNN.
Thanks for reading my point of view. Life's too short to stress out on small stuffs like this. Happy marketing and cooking to you.