Why can't I sell items in the demo?

[knowreturn]

So, I'm playing through the demo, and one of the things that frustrates me is that I collect a whole bunch of items in my adventure, but when I go to a merchant to sell it, most of it doesn't appear for sale. Outside of the potions, I get a couple of items per category that I can sell. Why is that? Is there something I'm missing here? To be honest, I've been cash poor the whole time. I get back to town, told to upgrade my equipment, but I don't have near the money to do that.

[MindfulOcean]

I'm playing the full game now and not the demo, but are you looking at the right stuff? In dungeons you collect a bunch of "trash" items, and so far, most of my money has come from selling those. I'm not super far into the game, but I've been saving gear just in case it is needed for different builds.