Buff163 or Swedish facebook CSGO trade groups is what I've used.
you can probably get in if you're norwegian but most people just accept "swish" as payment idk if they have that in norway.
but the prices are really good. usually 60-70% of the csmoney price or 90-98% of buff price
skinport and dmarket
cs.money scams more money out of you for 3 big skin purchases than if a scammer was to steal a knife from you, skinbaron is a bit better but still far from ideal