Buy a USED copy that is NON-STEAM. They go as cheap as $5.
Also: Ebay! Some awesome people there selling it even cheaper.
Id/Bethesda, you can't force people to buy the BFG: Edition, that's stupid.
I understand if alot of people love it, but you can't just try to take total control of things.
Beth isnt doing it, Amazon allows people to sell their own goods as well, and usually with releases like BFG, they will jack up the price.
I am not defending Beth or Id just pointing this out, when Halo Combat Evolved Anniversary came out, independent sellers on amazon where selling copies of the original game for 150 bucks a shot, not all of them though.