Am I just got getting how to make money?

I don't seem to ever be able to make money! I salvage everything but the traders never buy for much. Is there something I'm missing?

Yes, sell to players not NPCs. People will buy mats for a lot more than what the NPCs will give you.

If you don't want to bother with trying to get people to buy... the material trader NPCs will buy stuff like leather and iron for a decent price.