Modgud Gold (A Dual Magics Story) - Dual Magics, #1.5

Changing his apprenticeship from the Smiths' Guild to the Merchants' gives Arcas a second chance. Not just for a career that suits him far better, but also to prove himself worthy of the lovely Elaria. But to accomplish that, he must leave his seaside city-and Elaria-for a year. In that time, he travels among the barbarians, hoping to find something to trade for that will be worth the hardships and dangers.
Something like gold.