Many moons ago, I used to have a good friend called eBay. That friend though started charging me more and more for less and less help. It has gotten to the point now on eBay that the prices for things on there are quite often more expensive than going down to the nearby store. I left them for another friend.
That new friend of mine is Craigslist. For those of you not in the know, it's basically a free classified ad site with no third-party ads covering the site. It knows what it's there for and it does a great job at it. I had tried posting in local spots for people to rent our rooms and that went miserable, so I used Craigslist and haven't stopped using it since. For example, I picked up a storm door and a lawnmower this past weekend for $20 total from someone moving this week. In the past I've picked up a humidifier, dog kennel, manure and many more things.