Notice : Three different people have commented that they are not getting the credit for this deal. It may not be working properly. If you've tried to use it then I'd recommend escalating the request to customer support at Shutterfly and Visa to request resolution. - update added 9/28
Visa Checkout has a promotion right now with Shutterfly where they'll email you a $20 credit for Shutterfly if you use Visa Checkout to make a Shutterfly purchase.
The deal is good for orders made Sept. 1st till Nov. 3rd. You'll get the $20 promo code via email after using Visa Checkout for your purchase.
They don't seem to cite any minimum purchase requirement or other requirements for the initial purchase using Visa Checkout. I'm assuming / hoping then that you can use a promocode for a free photo book or similar and then pay for shipping using Visa checkout to qualify for that $20 promo. However I haven't verified that yet.
The details are below:
Annoyingly their website wouldn't let me copy/paste the text so I took a screenshot and above is a graphic.