If you aren't an Amazon prime member the shipping will increase to $49 minimum to get free shipping.
This does not include books which is still a $25 minimum.
source (http://techcrunch.com/2016/02/22/amazon-raises-its-free-shipping-minimum-to-49-for-non-prime-members/)
Seriously can't imagine not having Amazon Prime...that 2 day free shipping is a steal. Absolutely worth the price tag for me, but I also order quite a bit from them online.
same here
I don't order enough from Amazon to warrant the price for prime, though I'd consider it if I did.