Here are some posts from a local board I'm am member of from that time frame. You may notice, some WMs had the rollback, some didn't. I bought most of mine at the Delaware WMs; all of them participated in the rollback pricing. No VA, WV, or PA stores did. My job at the time had me on the roads all day everyday so I had the time to stop, and did so at every store during that time.
Here's a mention of it with prices listed:
https://www.mdshooters.com/showthread.php?t=171032&highlight=perfecta+.223
And on our ammo spotting thread, the Great WalMart Perfecta Rollback of 2015 starts getting mention on post #5449 and goes on for dozens of pages, including some shelf photos verifying prices:
https://www.mdshooters.com/showthread.php?t=112152&highlight=perfecta+.223&page=273
Here's some of the shelf pics from our local WMs at the time:
https://www.mdshooters.com/attachment.php?attachmentid=145333&d=1425602520
https://www.mdshooters.com/attachment.php?attachmentid=145332&d=1425602496
https://www.mdshooters.com/attachment.php?attachmentid=145331&d=1425602479
Unfortunately, I didn't find a shelf pic of the .223, but the $8.94/50 is mentioned in several posts, including post #6030 here:
https://www.mdshooters.com/showthread.php?t=112152&highlight=perfecta+.223&page=302