Okay, okay. You're like a couple weeks late for the really good stuff, but like next year--
End of college school, you hit the frat houses. The kids that have the money. Best dumpster diving in your life. All the stuff their parents bought them but are too lazy to move with, they just throw away. I found 60 bucks in a dumpster once. It's like they don't even care.
Apartment complexes have pretty good dumpsters. Stay away from restaurants, it's mostly gross food waste.
Craigslist is also good. Like sometimes people post free stuff to give away. But if it's furniture you might just need a buddy with a truck to help you come get it.