I play the two majors against eachother and sometimes throw in the independents around them. When I can save $3 on a kilo of bananas just by walking a few metres from the Coles enterance, then it's time to be aware of what's around you, and not just home in on their enterance like a moth to light. It's easy to ignore a 10/20c difference but when it's upto 50% one must pay attention. I guess Coles etc rely on those who don't.
Slightly off topic but on food. I planted a Rockmelon seed that was out of date by about 2 years and am enjoying the best freebie in recent weeks. Still fruiting due to Perth's warm weather and I will definitely plant more next year. I never had to time of day for crops like that, thought they were too much trouble with space, hence the old seeds, but now realise what I had been missing.