(1) The money in which the parties to a transaction have agreed that payment is to be made is the proper money of the claim for payment.\n(2) If the parties to a transaction have not otherwise agreed, the money of the claim, as in each case may be appropriate, is the money:\n(a) Regularly used between the parties as a matter of usage or course of dealing;\n(b) Used at the time of a transaction in international trade, by trade usage or common practice, for valuing or settling transactions in the particular commodity or service involved; or\n(c) In which the loss was ultimately felt or will be incurred by the party claimant. [1991 c.202 §5]
Oregon Legal Code