I've noticed in the Linux community whenever someone asks for a recommendation on a laptop that runs Linux the answer is always "Get a Thinkpad" yet Lenovo doesn't seem to be a big Linux contributor or ally. There's also at least six Linux/FOSS-oriented computer manufacturers now:
So what gives? Why the love for a primarily Windows-oriented laptop when there are better alternatives?
I usually look for corporate office liquidations in the paper or on social media. Other than that, I stop into colleges and businesses and ask them if they have hardware they need to recycle. Companies usually pay for recycling, so sometimes they will just give you stuff to lower their recycling cost.
And lastly, ebay if all else fails.