The formula

Saving on goods = home price − overseas cost. Difference after the trip = saving − travel − other trip costs. The saving is also the most the trip can cost before the purchase stops paying for it.

With the defaults: 800 − 500 = 300 saved, minus 150 travel and 80 other costs leaves 70. Count only costs the purchase causes: a trip you were taking anyway adds nothing extra. Read when a shopping trip pays for itself and whether buying electronics abroad is worth it.

Getting the overseas cost right

Use the landed-cost calculator to build the overseas figure: tax inside the price, a realistic refund, card fees and import tax at home. For several items, the travel basket combines them and keeps customs as one assessment.