Fixed delivery or delivery per item: quantity changes which offer is cheapest
By Erik Nilsen · Kroni3 min read
Two delivery options can use different pricing rules. One fixed charge may suit several items, while a per-item charge may be lower for a small order. Calculate delivery for the quantity your child actually wants, then add the product price.
Test one, three and four copies
In a hypothetical example, each optional notebook costs 10 units at both shops. Shop A charges a fixed 25 units for delivery of the relevant order. Shop B charges 8 per notebook. No other extras apply in the example. These arbitrary prices and delivery rules are invented.
With one notebook, A costs 10 + 25 = 35 units. B costs 10 + 8 = 18. With three, A costs 30 + 25 = 55, while B costs 30 + 3 × 8 = 54. B remains one unit cheaper.
With four, A costs 40 + 25 = 65. B costs 40 + 4 × 8 = 72. A is now 7 units cheaper. Product prices match; the entire difference comes from the delivery rule.
Find the crossover by comparing 25 with 8 times the quantity. 25 / 8 = 3.125. Since notebooks are bought whole, four is the first quantity with lower delivery at A. That does not mean your child should buy four if they want only three.
Keep the need fixed when comparing
A realistic snag is your child adding a fourth notebook to get the “best delivery”. Three at B cost 54, while four at A cost 65. The new item increases payment by 11, despite the more favourable delivery method for the larger quantity. Compare identical quantities first, then different actual purchases.
Check that fixed delivery really covers the desired quantity and product type. If a heavy or large order has an extra charge, write it on another line. Do not apply a fixed price from a different basket without checking.
Let your child fill in two columns for their own wanted quantity: products and delivery. Their sum must fit today's budget. A pricing rule does not promise that every possible order costs the same.
Ask your family: “How many do you actually want, and which delivery is cheapest for exactly that quantity?”
Carry the calculation into your family agreement
Kroni can keep track of your child's virtual balance. The app does not transfer money, so any actual purchase is paid for outside it. Agree on what you will record, then check the amount with your child afterwards. Do not deduct a possible cost as though the purchase had already happened. Read about allowance in Kroni.
