When you have kids and need to do the weekly shopping it's generally easier to go to one place and complete all your shopping. Rather than visit many shops within a shopping complex I used to visit just one large supermarket thinking that as a supermarket chain I would be getting better and best prices.
Well one day I visited an Italian delicatessen looking for some cookies I couldn't find in the supermarket and whilst browsing I noticed that the pasta was much cheaper as well as the sauces and cheeses. I was shocked at the large difference in prices and after chatting to the proprietor discovered they were buying from specialist suppliers that could buy better than the supermarkets and pass those savings onto their customers.
That experience encouraged me to visit all of the specialist food stores in our local shopping complex and found some cheaper and some more expensive than the supermarket chain. Overall I was able to save between $10 and $50 dollars by buying from different shops. The only drawback is that it takes me an extra hour to complete the weekly shopping task but the money savings are well worth the effort.