Best and cheapest way to find CF/TF 35-40 domains?

I want to build a PBN and I need really good quality sites. CF/TF 35 minimum.
I saw a few offers online but people are asking several thoudsands for really good domains.

I checked expired domains auctions a few times and such good domains are never being sold there.
So where do you get your CF/TF 35+ domains from at a good price? :)