Located in Ballard, just northeast of the Ballard Bridge at 1440 NW 52nd St. is the RE Store. They have your standard building salvage pieces along with some unusual and downright odd items. For unusual, last time I was there they had an ancient bidet or sits bathtub. The oddest thing they had then was clothing, from the 1950s or 60s that had been salvaged from a former dry cleaners. The items were apparently found behind a locked door that wasn't highly visible and had been forgotten about. The RE Store personnel discovered the door and found the old clothes. They weren't building supplies, but were too cool to scrap, so they salvaged them!
Price wise the RE Store is all over the board, from very pricey to downright reasonable, depending on what you want. I haven't tried dickering or doing a trade in, but hey, some of the stuff they get is donated, so I suppose you could try. One word of caution, make sure you know what you want before you go in, it's one of those"kid in the candy store" places for builders and remodelers.