Storage and junk items?

[Benyt]

Hello, as a beginner to this game, I have a couple questions regarding storage and what to do with junk items.

Over time, I've accumulated so many junk in my inventory that space is going to run out soon, so at this point, I'm looking for a storage. I've heard about retainers and inns, but which one is the main storage, the one that's meant to be used?

That's my first question. Secondly, should I sell the junk in my inventory or should I store them? For example, fish and drops by monsters. Apparently, they sell for very cheap at vendors, so I don't feel like it's worth selling them to those. If you say that I should put them in the markets, how would I figure out their appropriate prices?

Thanks for your help!