Quick answer
Define the destination, then list every cost needed to get usable inventory there.
The supplier price is the beginning of the cost stack. A good checklist separates sourcing and landed costs from later selling-channel costs so each decision is measured cleanly.
Supplier layer
Start with the complete purchase cost.
Confirm whether any charge is one-time or recurring. One-time tooling should not automatically be treated as a permanent unit cost without an allocation policy.
Origin and freight layer
Match the logistics costs to the Incoterm.
Do not add freight twice when it is already included in CIF or another quoted basis. Use the written quote scope rather than the Incoterm label alone.
Border layer
Document both the rate and the base.
A duty percentage without the customs-value basis is incomplete. Keep the classification, rate source and valuation assumption with the calculation.
Destination layer
Bring the goods to the destination used in the model.
Selling layer
Keep channel economics separate from landed cost.
Marketplace commission, fulfillment, payment processing, advertising, customer delivery, returns and sales taxes may be important for profit, but they are not always part of landed cost. Keep them in a second layer so the sourcing cost and selling economics remain understandable.
Final review