I have gotten a few Macs for free.
A friend found a working PowerMac G4 MDD and a non-working 27" Mid-2011 iMac a dumpster at his work.
He wanted the iMac, but couldn't get to work, so he gave them both to me.
After baking the GPU in the oven and replacing the HDD with a SSD, I got it working. It ended up being a top of the line BTO, with the i7 and 2GB GPU. The 2GB GPU was rare for that model, and sells for over $600 on eBay.
I gave it back to him, or I should say sold it back to him for the price of the SSD, but I still have the PM G4. On day, I will mess with it, and probably put some SSDs in it.