Though Amazon has never officially participated in Free Shipping Day, they're still free shipping pioneers. They regularly offer free two-day shipping without even having to use a coupon.
No matter what you're shopping for, you'll probably be able to find it on Amazon.com. They also have a ton of free services like the Amazon Cloud Drive which provides 5GB of media storage you can access anywhere.
To make sure you get the best discount possible at Amazon.com, make sure you check this page for the latest coupons. New deals are always available, so you never know what you might find.
8lbs of Lucky Charms marshmallows, a Ben & Jerry's pint lock and glow-in-the-dark toilet paper are just some of the extremely weird things you can actually buy on Amazon. But, if you need normal things, you'll also find them there.
But fair warning: as the biggest online retailer for just about anything, you could get lost in the cyber aisles!