This offer is still available in case you may have missed this last year.
To get FREE 25 1-Hour 4X6 Prints at Walmart you need to sign up a new account at Walmart Photo, simply scroll to the bottom of the page and click the offer. Walmart will then email you a code for 25 FREE 1-Hour 4X6 Prints (the email may take up to 24-48 hours to come). Once you get your email just follow the instructions in your email to get your FREE prints. Be sure to select in-store pick up, to make it 100% Free.
Here is the direct link to the offer.