Shelf Price vs Paid Price: What You Really Paid Per Unit

Look at the bottom half of a supermarket receipt and you will often find lines that do not belong to any product name: “DISCOUNT”, “PROMO”, “MULTIBUY”, or on Turkish receipts “İNDİRİM” and “KAMPANYA”. They lower the total, but they do not change the price printed next to the item. So the receipt carries two prices for the same product: the shelf price and the price you actually paid.

Two prices, two questions

• Shelf price is the regular price on the item line. It answers: what does this product normally cost at this store?
• Paid price is what the item cost you once its discounts are taken into account. It answers: what did I really spend on it?

Both are useful. If you only track shelf prices, you overstate what you spend and miss the value of the deals you took. If you only track paid prices, a promotion looks like a permanent price drop and the end of the promotion looks like a price hike.

A worked example

Here is part of a receipt with a multi-buy offer on yoghurt and a coupon on coffee:

Line	Qty	Unit price	Line total
Yoghurt 500 g	2	$2.80	$5.60
Coffee 500 g	1	$8.40	$8.40
Bananas	1.2 kg	$1.50 / kg	$1.80
MULTIBUY yoghurt			−$0.60
COUPON coffee			−$1.00
Total			$14.20

The item lines show shelf prices. Spreading each discount over the line it belongs to:

• Yoghurt: $5.60 − $0.60 = $5.00 for two pots, so $2.50 per pot. Per kg: shelf $5.60, paid $5.00.
• Coffee: $8.40 − $1.00 = $7.40. Per kg: shelf $16.80, paid $14.80.
• Bananas: no discount, so shelf and paid are both $1.50 per kg.

On this receipt, the paid unit price of coffee is about 12 % below its shelf unit price. If next month you pay the full $8.40, your coffee did not get 12 % more expensive. The coupon simply did not apply.

Basket discounts are harder

Some discounts belong to the whole basket, for example “$3 off when you spend $50”. There is no single line they belong to. The fair way to handle them is to spread them over the lines they apply to, so each item carries its share. One common way is in proportion to each line’s total: an item that is 10 % of the qualifying basket takes 10 % of the discount.

Doing that by hand for a 30-line receipt is exactly the kind of work that makes people give up on tracking prices.

Turkish receipts in particular

Turkish till receipts have their own patterns that affect unit prices:

• “KG X” lines show a weighed item: the weight and the price per kilogram.
• “AD X” lines show a counted item: the number of pieces (adet) and the price per piece.
• VAT at 1 %, 10 % and 20 % is listed per rate, which helps check that the lines add up.
• İNDİRİM and KAMPANYA lines are discounts, sometimes directly under the item, sometimes grouped at the bottom.

Reading these correctly is what turns a receipt into a reliable paid unit price.

Why keep both, not just one

Keeping both prices side by side tells you things neither one tells alone:

• Is a product really getting more expensive? Watch the shelf unit price.
• Are you getting good deals on it? Compare paid with shelf.
• What did your basket actually cost? Add up paid prices.
• Is a “deal” really a deal? Compare today’s paid unit price with the lowest you ever paid. See why keep your own price history.

Both prices should also be compared per unit, so that a promotion on a bigger pack does not look like a bargain when it is not. See how to compare unit prices.

How Tasarruf helps

Tasarruf reads discount and campaign lines along with the items, spreads discounts over the lines they belong to, and keeps the shelf unit price and the paid unit price separately for every product. It checks that lines minus discounts add up to the total and highlights anything that does not, so the numbers you track are the numbers you paid. See Tasarruf.