Methods, including service methods, articles of manufacture, systems, articles and programmable devices are provided for linking and utilizing monetary and carbon credit accounts through a programmable arbitrating device providing a transaction interface to the buyer. A composite price is set for an item having a monetary portion and a carbon credit portion, a buyer executing a purchase of the item through an input to the arbitrating device transaction interface, the arbitrating device automatically charging a monetary payments from the buyer's monetary account, carbon credit payments from the buyer's carbon credit account, a difference between the payments and the composite price debited to the buyer's carbon credit account balance for a monetary value of the difference as a function of a monetary-carbon exchange rate, or to the buyer's monetary account for a carbon credit value of the difference as a function of the monetary-carbon exchange rate.