Start from the checkout price
The visible price is only the beginning. Add shipping, currency conversion fees, payment fees, and any expected taxes before comparing it with a domestic alternative.
Watch the threshold
Many countries have thresholds that change whether tax or duty applies. A small shipping fee or currency move can push an order above the threshold.
Compare the final choice
The overseas option is attractive only when the estimated landed cost is meaningfully lower than buying locally, after considering returns, warranty, delivery time, and support.