Buying a large freezer can be an excellent investment. I got a large chest freezer a couple of years ago when I ran a business, and needed it to make ice, second hand it cost $150. Food is frequently available at very cheap prices in bulk, especially from markets.

Just before closing time supermarkets frequently slash prices on perishables, deli stuff, fruit and veg, and especially bread. I have bought a kilo of salami for 20c, fresh bread for 15c, sea food is usually half price, I got virtually the entire contents of the Coles cake fridge for $2.50 the lot. Chicken pieces go on special for less than $2.00 a kg all the time, at the wholesale market on saturday morning I buy enormous boxes of fruit, oranges, mangos, peaches, the lot, for only a few dollars when they are in season. These aren't one off events, although usually things get cleared for a bit more than this most weeks, big discounts in the last 5 minutes of trade when the manager has instructed the staff to clear the lot happen all the time. Some supermarkets are better than others though, so look around.

I was talking about this once with a friend, who suggested perhaps that tying up money in having all that frozen food like this was not the best idea, you could invest that money instead. Given that I save anything from 40% to 80% on food, and the total "float" (amount of money sitting around in the form of a freezer full of food) is unlikely to be more than a couple of hundred dollars at most, there is virtually no chance that any investment could ever make me as much money as this tactic saves me, and certainly not without big risks.

The other thing you can do to save on groceries is to read all your food junk mail. Supermarkets are putting out loss-leaders, super cheap products to get people into the store all the time. Although it probably is a bit annoying to the supermarkets concerned, my freezer is always filled to the lid with loss-leaders. Having food on hand means you don't have to go out and spend $40 buying the family junk food, if you want something tasty but unhealthy a good frozen pizza costs $3.00 on special.

Lastly, remember the generic brands. Ok, some of the plain wrap stuff isn't much good, a fish finger is this little tiny slivver of fish coated in a thick pasty sludge deceptively referred to as "batter", but not all plain wrap food is like that. Ever looked closely at the bottles of milk in the supermarket? In Western Australia there are only really three brands of milk. Brownes, Masters and Harvey Fresh. So what are all those other things, Premium Brand, Royal Harvest, Woolworths etc. etc.? Mostly they are Masters or Brownes, if you want to know which exactly you look at the shape of the bottle. Years ago I ran a milk delivery business, I saw the guy filling bottles of the expensive premium brand, stop the machine, change over to the other bottle tops and labels and start it up again. Branding is important to manufacturers and people are willing to pay a hefty price premium for the brand they trust. I didn't see them all breaking out the cigarettes and knocking the ash into the pasteurisation machine when they started making the cheap stuff, so presumably your $2.00 a week spent buying the premium brands instead of the cheap one is money wasted.