Buy in bulk
There's a reason that the Canberra Costco store got to 50,000 members in its first year. Every weekend the megastore is packed with hundreds of people pushing those huge trolleys and loading up on pallets of food, kilos of meat, and huge boxes of fruit. It's a sensible way to cheaply feed a family. You still need to check prices and compare them with your local supermarket though, to make sure you get the best bargain. If you're single, split the cost of membership with someone, or go in with a friend who already has a card. A family-sized couscous salad can give you a week of packed lunches for less than $10.

Have a plan B for everything you buy
Don't let anything go to waste. If you cook a meal and find yourself with leftover raw ingredients, put them to work. Relax editor Karen Hardy suggests using an online service called Eat Your Books, which allows you to trawl through your cookbook collection and find recipes using the ingredients you've got on hand. Plan your meals according to the likelihood of leftover ingredients - that whole roast chicken means you'll have shredded chicken sandwiches for lunch the next day and a chicken soup made from the carcass for dinner.

Dress up cheap ingredients
There's a reason that so much of the world's great street and peasant food involves rice, pasta and easy carbohydrates. Cook a cupful of rice, throw in a cupful of veg and fry it all up with an egg. Spinach is super cheap, blend it up with a clove of garlic, some olive oil and a handful of pine nuts and it becomes a nutritious sauce for pasta. Take an off cut of meat such as brisket and cook it low and slow with some carrots and potatoes. Or start becoming friends with ground meat, which you can stretch out in stir fries.

Make price lists
Keep track of what you spend with an app. If you have an iPhone, Grocery Gadget Shopping allows you to make grocery lists and scan products at the supermarket. Value Tracker ($1.29) and Grocery Helper (free but only updated to 2010) both allow you to track the price of groceries over time so you can tell if you're getting a bargain. And Unit Price Free (free) calculates prices per unit. If you get really lazy, just take a photo of the price of each grocery item on your phone and add it to a special album. Or do it the old school way - keep a small notebook in your bag. Devote a page to each product you want to track and write the price down each time you purchase. Use a pencil or a post-it label to mark the lowest price.

Second-hand and sales
You still need to have good tools. Join mailing lists such as Freecycle and keep an eye on classified websites such as buyandsell.com.au (owned by Fairfax Media, publisher of this website) or eBay to find unwanted or preloved kitchen appliances going cheap or free. Check out book fairs for second-hand cookbooks and don't turn up your nose at older books. Delia Smith's seminal work on the topic, Frugal Food, was first published in 1976.