hi! for additional information, check out responses in these related questions ~

• What was the relationship between the Sami and the Vikings like?

• What was the relationship bettween the vikings and the samii people?

• What was the relationship between the Sami people and the so called "Vikings"?

• Did the Sami (also known as Laplanders) ever war with the Vikings, if so why?

When a saga talks of a 'Finn' or 'Lapp', it's referring to the Sami. Thus when Ottar ('Ohthere') speaks of his income coming mainly from tribute paid by the 'Finns', that's presumably evidence of violence at some point in the past - we may take it that the Sami didn't give him valuable furs out of the goodness of their hearts:

[Ottar's] estate consisted of no more than twenty cattle and the same amount of sheep and swine each, and there was some minor ploughing with horses. The Lapps however pay tribute to them, which adds to their property: deer hide, feathers, whale-bone, and ship rope which is fabricated from the hides of seal and whale. The amount of tax depends on the tributee's rank. The most high-born must donate fifty marten's hides, five reindeers, a bear hide, ten ambers (an unknown quantity) of feathers, a garment made from bear or otter hide, and two ship ropes which must be sixty ells long and made from whale or seal skin.