To sell you need to be in a city. Then you gotta open up your character menu, and stick the items you want to sell in the "Discard" box, and it will sell.
To beat the bosses it isn't luck...You need to get battle trance. To get it you must land more attacks on your opponent. That also includes taunting, which it helpful.
I like the game, but it is disappointing knowing it's a demo. 4/5.
The thing that really pissed me off was that when i would go near one of those spike things i would die, instead of actually touching it. Other then that, good game. 5/5.