Students will learn how to determine 'price per unit' to help make decisions when comparing products.


Choice, Consumer Economics, Decision Making, Incentive, Price


  • Demonstrate how to determine price per unit.
  • Understand what is the 'best deal' when comparing prices.
  • Explain why a consumer might, in some cases, purposely not choose the best deal.
  • Discuss other marketing techniques that influence consumer decisions when comparing prices.


candybarReview the familiar situation described in the Students' Version. A customer walks into a store to make a quick purchase-- maybe it's a candy bar or a can of soda pop. She picks something up for 75 cents. Then, just to the side she notices a small ad for a similar product that reads, 'New larger size, only 95 cents!' Now what? Does she go with the original item or switch? Which is the better deal? Is bigger always better?


  • Compare Prices Story: This interactive story points out to students that buying in bulk is not always the best option.
    Short Story


Demonstrate how to determine price per unit. To do this, take the price and divide it by the number of units. All examples and problems in this lesson are rounded to the nearest cent.

Example: 20 ounces of soda pop for 95 cents is $0.95/20 ounces = $0.05 per ounce
Compare this to 12 ounces of soda pop for 75 cents or $0.75/12 ounces = $0.06 per ounce.

The key to comparing prices is to break the cost down to a price per unit. For example, a 20 ounce bottle of soda pop may cost $0.95 and a 12 ounce bottle of soda pop may cost $0.75. To determine the better deal, you want to compare the price per unit [in this case, the price of one ounce of soda pop]. To find this, divide the price by the number of units.

popFor the 20 ounce bottle, you divide $0.95 by 20. This equals $0.0475 per ounce of soda pop. In this lesson we will round to the nearest penny, so the answer would be rounded to $0.05 per ounce of soda pop.

For the 12 ounce bottle, you divide $0.75 by 12. This equals $0.0625 or $0.06 per ounce of soda pop. Which one is the better deal? [Based on price only, the 20 ounces of soda pop is the better deal.]

You may want to create additional examples, or have your students develop examples of their own, for more practice.

[NOTE: This lesson is based on 'like' units with no unit conversions required. For example, there will not be problems with one item supplied in gallons and another in liters [1 gallon of milk at $2.60 vs 2 liters of milk at $3.00) or one item sold in pieces and another by the pound (30 pieces of candy at $5.00 vs. one pound at $4.00].

For guided practice, have students complete the Best Deal Challenge. You can decide if you want to allow students to use calculators or not. Several problems can be solved with mental math (2 pops for $1.00 vs 3 pops for $2.00). This could also be a point of discussion with your students as to what consumers typically do. Some shoppers carry calculators with them for this purpose or use a PDA application like CostComp [Download and show this to your students if you have a PDA].

Look at this short story (to precede through the interactive story use the right arrow key on your keyboard). [This pertains to Problem 6 in the Best Deal Challenge, providing a way to launch a discussion about considerations other than just price.] Ask students, 'When are there times you would choose to not take the best deal?' [Possible answers: sometimes you just don't need 10,000 cups - too much in bulk purchases at times, or not enough money to buy 5 video games at once, brand name loyalty, loyalty to a particular merchant if comparing prices between stores, the quality of the product, convenience, some products like computers and video game systems come with more than just price to consider-- for example, the warranty, special features, etc.]

If it isn't brought up by a student, also point out that sometimes producers offer 'incentives,' or a special reason to buy their product. An incentive might be a discount, like a coupon, or a 'gift' like a toy in a cereal box. Incentives may prompt consumers want to buy one product instead of another product.

[NOTE: This information is from the Clipping Coupons lesson, a related lesson.]


To have students demonstrate that they know how to determine price per unit, use the The Best Deal worksheet or simply use a blank sheet of paper. Students need to create a pricing problem similar to the Best Deal Challenge activity. Students should fold the sheet over to the dashed line so the answers are covered. They need to think of a product and three ways to price it. Students can either draw or write the examples on the front of the sheet. On the inside, they should show the answer revealed, and also have the price per unit of each choice shown. Once you have checked the students' work for accuracy, have them share their problem with classmates for additional practice.


Encourage your students to apply what they learned in this lesson in a real-life situation like the following example. Ask students to suggest some other real-life applications.

The next time you go to a grocery store, take along a calculator to determine the price per unit of some items you or your family might purchase. Some grocery stores already have this information posted for you (you may want to check to see if they are right!). Bring this information back to your class and discuss it with others to explain how determining price per unit influenced your shopping decisions. Where else could you apply what you learned in this lesson?


1. If possible, take a class field trip to a store for more practice, or have students bring in items to create a class store.

2. For a project idea, have students create a multimedia project similar to the Best Deal Challenge. One slide or card could show a problem, and the choices could be linked to the answers. There are several programs and ways to make this happen - you could even incorporate digital video.

3. A related lesson link that would be beneficial when teaching this lesson is this Financial Fitness for Life activity.


  • “Great real life situations in the Fitness for Life! It really makes the kids think.”

    G. Spencer, Brookfield, WI   POSTED ON April 14, 2008

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