Elsewhere in Europe, coins began to enter circulation as early as the so-called Merovingian period (around AD 550–800).
In Norway, however, they only began to be minted late in the 9th century, towards the end of the Viking Age. Before this point, barter economies were common in the Nordic countries, with the weight economy making inroads around the end of the 8th century.
According to Prof. Maixner, “the weight economy was a much more flexible system than the barter economy.”
In the latter, for example, she explained, ”you had to have a fair number of sheep if you wanted to exchange them for a cow.
“Weighed silver, on the other hand, was easy to handle and transport, and you could buy the goods you wanted when it worked for you.”
Article source: https://www.express.co.uk/news/science/1692810/viking-age-silver-treasure-trove-unearthed-norway-metal-detectorist-hacksilver