I dont know where you live, but we have a place in Nashville called Southeastern Salvage. If you are there when they get things in, it is dirt cheap. They have great deals on Granite, hardwood, laminate, carpet, decorations etc. I got some really cute pictures that I had seen on art.com for $129 for $9!!! They run Bruce hardwood for $2 a square foot for a while.
Craigslist is also a great place. We have bought several things there. It is good for appliances, sinks, etc.
Light fixtures we have just run across deals at Lowes. We go in a lot just to check and see if they have put any clearance out.
We also have Habitat for Humanity reuse stores here. It is where major stores donate to Habitat, and instead of using it, they sell it in the stores.