I have posted a few times about the way to Shutterfly hack… Yes you can stack freebie codes. The best way to make your purchase cheaper per item is to stack a bunch of freebie items with item(s) that add up to the free shipping amount, so that you can add that code as well.
Most of the time the free shipping minimum is $39, so if you order non freebie items, even if they are discounted with a code or already on sale on the site, totaling $39 you can get everything shipped free (except magnets I think).
Where do you get freebie codes…. NUMBER ONE RULE: look at H2S onlinements; I often find other codes posted by readers.. for example, you can get a set of pencils with code… PENCILS! Additionally when people post that they have codes for freebies from emails, I sign up to receive emails from those onlinepanies. I have also noticed a pattern with Shutterfly lately where they have multiple freebies on weekends. That is when I usually get my best deals.