Amazon has free shipping, as long as you don't use the 1-Click purchase, as it's not set up to give you this option. This is from my email yesterday, from Amazon customer service..
Our system also won't automatically apply the Super Saver Shipping option to qualifying orders, and Super Saver Shipping can't be the default 1-Click shipping method. I'm sorry if this was unclear when you placed your order.
I see your order would've qualified for free shipping, so I've made a one-time exception and requested a refund of the shipping costs for this order. You'll see a credit of $2.98 in the next 2-3 business days.
If you want to use Super Saver Shipping in the future, I'd recommend placing the order through the Shopping Cart, where you can manually select Super Saver Shipping as your shipping method.