Customs valuation principles: transaction value rules and required inclusions and exclusions for determining import value. Customs valuation relies principally on the transaction value-the price actually paid or payable including non monetary payments-excluding post import charges and domestic duties when distinguished. Transaction value may be rejected when price depends on conditions or considerations not determinable with respect to the imported goods, while restrictions not substantially affecting value are acceptable. Buyer undertakings on its own account are not indirect payments unless an adjustment rule applies.