Fiona Lippey is the founder of Simple Savings.
"The average family who spend about $300 a week on food are usually making big mistakes," she said.
"They're usually buying expensive packet food, they're usually paying premium prices and they are just not thinking."
More stories from Today TonightFiona said a lot of people buy food and then forget they have it.
"It sits in the back of the cupboard and goes rusty and it just gets wasted," she said.
"Ten percent of all food grown is wasted."
By using what is on hand, Fiona argues average families could save $200 to $250 a month.
Members of Fiona's online club have already proven it can be done.
"The reason why it's $21 is because one of our members Barb's husband only brought her home $20 to do her weekly shop and she found $1 in her purse and she said 'I'll show him' and she took it on," Fiona said.
"She told us and then our members went for it and now there's thousands of people who manage to do their weekly shop with just $21."
Nutritionist Julie Gilbert warns families should not use plans like Fiona's too often.
"If I had $21 to feed my family I would look at things like fruit and vegetables particularly at those that are in season and on special," she said.
"I'd also make sure I'd get a loaf of multi-grain bread and also some low fat milk."
How to get started1. The $21 Challenge was originally created to feed a family of four, but larger families have successfully adapted the plan to feed more. Feel free to add an extra $5.25 per person to your overall budget goal. But many families have finished the week having spent much less than $21!
2. There is no point taking the challenge when you are hosting visitors, on holidays, moving house or nursing sick family members.
3. Immerse yourself in the pantry, dig deep into the freezer and explore every inch of the fridge. Get rid of anything past its use-by date. Jot down everything else. Use the categories 'Regulars' (items you buy and use all the time) and 'Bonuses' (things you bought ages ago and do not really know what to do with). When you stocktake the fridge, note any items that need to be consumed within the next week.
4. This is really the key to conquering the $21 Challenge. Unlike traditional menu plans, this one works backwards, starting with what you have and then working out what wonderful things you can do with it.
5. Use your own family-friendly recipe books, consult The $21 Challenge book or check out recipe websites like Yahoo!7 Food.
6. Making a shopping list is the easiest thing to do this while you are filling in your planner, jotting down any recipe ingredients you do not already have. Estimate the total cost and make adjustments where you can.
7. Stick to your list and do not be tempted by any of the sneaky tricks supermarkets employ to try to take your hard-earned cash.
List of Recession Busters storiesRecession Busters: Groceries
Recession busters: Medicines
Recession Busters: Telecommunications
Recession Busters: Gas, electricity and water
Recession Busters: Home, car insurance
Recession Busters: Health insurance
Contact details
The $21 food information can be found at www.simplesavings.com.au.
Please note, membership fees may apply.
''DisclaimerThe information on yahoo7.com.au/todaytonight is made available for information purposes only, and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Also, the accuracy, currency and completeness of the information is not guaranteed. Yahoo!7 and The Seven Network do not accept any liability for any injury, loss or damage incurred by use of or reliance on the information.''
