Coupons and deals: which offer saves more?

0:00Juice is $6 a bottle, and you need 3 bottles.

0:04Deal A is buy 2, get 1 free. Deal B is 30% off. Which is the best buy, the one that costs least?

0:14With no deal, 3 times $6 is $18, the full price.

0:20Deal A means you pay for 2 bottles and get the third one free.

0:25So Deal A costs 2 times $6, which is $12 for 3 bottles.

0:32The unit price is the cost of one item. For Deal A, $12 divided by 3 is $4 a bottle.

0:41Deal B is a discount, an amount taken off the price. 30% of $6 is 0.3 times 6, which is $1.80.

0:52Take that off: $6 minus $1.80 leaves $4.20 a bottle. Check: you pay 70%, and 0.7 times $6 is also $4.20.

1:07For 3 bottles, Deal B costs 3 times $4.20, which is $12.60.

1:16Side by side, Deal A costs $12 and Deal B costs $12.60.

1:23Against the full $18, Deal A saves $6 and Deal B saves $5.40. Deal A is the best buy for 3.

1:35But if you need only 1 bottle, Deal A gives nothing free, so you pay $6.

1:42Deal B charges $4.20, which is $1.80 less, so for 1 bottle, Deal B is the best buy.

1:52A common mistake is buying extra just to use a deal. Paying $12 for 3 bottles is not a saving if you need only 1.

2:01A coupon takes a fixed amount off. To compare it with a percent deal, change it to a percent.

2:08A $2 coupon on a $9 item: 2 divided by 9 is about 0.22, so about 22% off.

2:18For 3 bottles Deal A wins, and for 1 bottle Deal B wins. The best buy costs least for what you need.