I am in arelium right now, trying to interact with the tinker...
i type in "talk to (whatever his name is)" and it just says "(whatever his name is) ignores you"
i have all this junk but i can figure out how to sell it!
what do i do?

and for that matter, why do so many people ignore me? i say 'talk to (whoever)" and its always like "(whoever) ignores you"
am i doing something wrong?

It's actually relatively more simple than you think. You can use 'list' to view all the goods that the shopkeeper has to offer, 'buy' to buy an item, and 'sell' to sell an item. Weaponsmiths will only buy weapons from you, armourers armour, and the general store, well...the rest of the junk mostly. You can use 'sell sword' or 'sell o-yoroi' and it'll sell the first item in your inventory that meets that description.

And for cheap stuff (under 20 gp) you can toss them into a trashbin(found in shops) and get some gold.

Most of the NPC do not talk to players.

How can I use trashcans? :)

No need to answer. I know it now. :)