I have a hidden secret I am going to share with you. I love this place. It is a mess and most of the stuff is used but you can get great deals if you are willing to dig and maybe clean the things when you get home.
There is a place called ReStore. It is owned and ran by Habitat for Humanity.
I have gone to the local ones around here for the last 4 or so years and I am never disappointed. I always find something and it is usually dirt cheap. A little elbow grease and imagination and you get great stuff. Best of all is that almost all of the money you spend goes back to building more houses. Go to this link to see if there is one local to you http://www.habitat.org/cd/env/restoreUS.aspx
My latest trip I actually tried a newer to the area one and I didn't love it as much as the one I typically go to. If you are in my area the one in Azusa is great. Montclair, not as much. I did however some home with a new lock and handle for out back sliding door that I spent $2 on and it was brand new. The coolest thing in my treasure hunt was a new to our house old screen door. It is the real deal. It is all metal screen and in pretty good condition. I got it for $5. I need to fix a few screws but nothing hard to do at all. So my projects for the day were fixing our door handle and when it cools down a bit I will get the new screen up and working. I wasn't sure if it was the right size but it is spot on exact once I got it home. So now that I gave away one of my hidden gems go check it out. If you do, share what you found.