Best buys and value for money

Quick answer

Best buys and value for money means comparing prices to find which product gives you the most for your money. You do this by working out the price per unit, like how much each apple costs or how much each litre of juice costs.

Learning outcome

By the end of this page, you will be able to compare prices to find the best buy by calculating the cost per unit.

• You can tell which item gives the most for your money
• You can work out how much one item costs
• You can compare prices of different sizes or packs
• You can make smart shopping choices

Why this matters

Knowing about best buys and value for money helps you save money when shopping. It's like being a detective, finding the deal that gives you the most for your pocket money or your parents' money. This skill helps you in everyday life, like when you're helping your family buy groceries or when you're saving up to buy something special. It also helps you understand how stores price their products and makes you more confident in maths.

How it works

Here's how to find the best buy:

1. Look at the price and size of two or more products
2. Work out the cost per unit (like per litre, per kilogram, or per item)
3. Compare the prices per unit
4. Choose the one with the lowest price per unit

For example, if one pack of juice costs £2 for 1 litre and another costs £3 for 1.5 litres, you need to work out how much each litre costs to see which is better value.

Examples you can see

Let's look at some fun examples to understand best buys:

Example 1: Apples

You're at the shop and see two bags of apples:

• Bag A: 2 kg for £3
• Bag B: 3 kg for £4

Work out how much each kilogram costs:

• Bag A: £3 ÷ 2 kg = £1.50 per kg
• Bag B: £4 ÷ 3 kg = £1.33 per kg (rounded to 2 decimal places)

Bag B is the best buy! It costs less per kilogram.

Example 2: Milk

Compare these milk packs:

• Small pack: 500 ml for £1.20
• Large pack: 1 litre for £2.20

First, make sure the units are the same:

• Small pack: 500 ml = £1.20
• Large pack: 1000 ml = £2.20

Now calculate the cost per millilitre:

• Small pack: £1.20 ÷ 500 ml = £0.0024 per ml
• Large pack: £2.20 ÷ 1000 ml = £0.0022 per ml

The large pack is the better value! It costs less per millilitre.

Example 3: Chocolate Bars

Compare these chocolate bars:

• Bar A: 10 bars for £5
• Bar B: 15 bars for £7

Work out the cost per bar:

• Bar A: £5 ÷ 10 = £0.50 per bar
• Bar B: £7 ÷ 15 = £0.47 per bar (rounded)

Bar B is the better buy! It costs less per bar.

Try it as a mini adventure

Adventure: The Shopping Detective

You're a detective on a mission to find the best buy for your family's weekly shop. You have a budget of £10 and must choose items that give the best value. Here's your challenge:

1. Find 3 different packs of the same product (like cereal, pasta, or juice)
2. Write down the price and size of each pack
3. Calculate the cost per unit for each pack
4. Choose the best buy and explain why

Example:

For cereal:

• Pack 1: 500 g for £2.50
• Pack 2: 750 g for £3.50
• Pack 3: 1 kg for £4.00

Work out the cost per gram:

• Pack 1: £2.50 ÷ 500 g = £0.005 per g
• Pack 2: £3.50 ÷ 750 g = £0.0047 per g
• Pack 3: £4.00 ÷ 1000 g = £0.004 per g

Pack 3 is the best buy! It costs the least per gram.

Common mistakes

• Mistake: Looking only at the total price instead of the price per unit.
• Why it happens: Children may think a bigger pack is always better, not realising that the price per unit matters.
• Fix: Always calculate the cost per unit to compare fairly.

• Mistake: Not making the units the same before comparing.
• Why it happens: Children might compare 100 ml with 1 litre without converting.
• Fix: Convert all units to the same size before calculating.

• Mistake: Forgetting to round decimals when comparing prices.
• Why it happens: It's easy to get confused with long decimal numbers.
• Fix: Round to 2 decimal places for easier comparison.

Parent and carer guide

Helping your child understand best buys and value for money:

• Look at shopping receipts together and compare prices of similar items
• Ask your child to find the best buy for a family favourite
• Use everyday shopping to practice calculations
• Encourage your child to explain their thinking
• Make it fun with games and challenges
• Don't worry if they make mistakes – they're learning!
• Remember that this skill helps children become more confident with maths
• Ask questions like "Why do you think that one is better value?" to encourage thinking
• Use real products at home to make it practical
• Be patient and celebrate small successes

Practice questions

1. Which is the better buy: 500 g for £1.20 or 750 g for £1.80?
2. Compare 100 ml for £0.50 and 250 ml for £1.25. Which is better?
3. Find the best buy: 2 kg for £4 or 3 kg for £5.50
4. Which costs less per item: 6 eggs for £1.50 or 12 eggs for £2.80?
5. Compare 1 litre for £2.40 and 1.5 litres for £3.60. Which is better value?

Answers:

1. 750 g for £1.80 (costs £0.24 per 100 g vs £0.24 per 100 g – they're equal)
2. 250 ml for £1.25 (costs £0.50 per 100 ml vs £0.50 per 100 ml – they're equal)
3. 3 kg for £5.50 (costs £1.83 per kg vs £2 per kg)
4. 12 eggs for £2.80 (costs £0.23 per egg vs £0.25 per egg)
5. They are the same value (both £2.40 per litre)

FAQ

What is the best way to find the best buy?

The best way is to calculate the cost per unit, such as the cost per kilogram or per litre. This helps you compare different sizes fairly.

Why is it important to know about best buys?

Knowing about best buys helps you save money and make smart shopping choices. It's a useful life skill that helps you get the most value from your money.

How can I practice this at home?

You can look at product labels, compare prices, and calculate the cost per unit. Try to find the best buy for items you use regularly like milk, cereal, or fruit.

What if the units are different?

Always convert the units to the same size before comparing. For example, if one item is in litres and another in millilitres, convert them to the same unit first.

Can this help with other maths skills?

Yes! It helps with division, fractions, decimals, and comparing numbers. It also builds problem-solving skills and real-life maths confidence.