Create or login to your account, upload a photo, and use the following code to make an 4×6 print free: (Expires at 2:59pm ET): FLASHLUCK
The code may not work in the Walgeens App.
You can pick-up in any Walgreens store for free or ship it to your home for $1.99.
Be sure that you upload pictures in full resolution for best results, click on upload preferences and change to full resolution. You may also want to uncheck the color correct option.