Comment: The toll is a current expenditure, not a debt repayment,

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In reply to comment: Well, that was my thought too... (see in situ)

The toll is a current expenditure, not a debt repayment,

so the vendor an set their payment terms as they wish.

You may have also seen signs from sellers saying "No bills over $20 accepted", which is also valid when it applies to current transactions, as opposed to repayment of previously incurred debts.

At least that's my understanding...