Amazon lowers free shipping threshold back to $35 (http://money.cnn.com/2017/02/21/pf/amazon-lowers-free-shipping-non-prime-membership/) (from $49).
Not directly/specifically gaming related, but I know a lot of us buy game books through Amazon, so thought it would be useful info and didn't see a thread already.
Of course, you still get free shipping with $25 worth of eligible books, which already covered a lot of games, but may not cover box sets, board games, and other things of gaming interest (dice, minis, etc).