I too, try to support the local small shops rather than one of the chains, but it isn't always easy. One thing I've noticed though is that the quality of fresh vegies in Port, and South Melbourne Coles/Safeway, and the variety thereof, is a level above that in the same shops in Mitcham/Ringwood. The more effluent get the better quality.
What I find incredible about some comments on this subject is the notion of price control, or rather price fixing, in the Land of the Free.
In Aust. it is illegal to set prices (theoretically anyway - I've no doubt there is collusion between the bigger players in supermarkets and petrol).
This sounds anti-competitive to me.
GG