Almost anything used to the point of being trashed can be had free, but what are some things that are expensive brand new, but can usually be found for free used, while still in good condition (not from family or close friends)?
An example I can vouch for is pool tables. A quick craiglist search will almost always yield at least a couple of people giving away pool tables if you just go and move it out of their house for them. A friend and I once went and picked one up and put it in his backyard (there wasn’t any room in his house for it). It wasn’t a slate top, just plywood, so after a few storms it got all warped, but we got a couple of months’ worth of pool out of it.
Pianos. Nobody knows how to play the thing anymore, and/or they’re moving and don’t want to have to move the thing. I’m not sure why anyone buys new pianos anymore.