Walmart prices vary regionally. Back in 2008 during the last ammo panic, walmart still was getting ammo in reliably. It didn't stay on the shelves long, but they did get it in stock. As I recall, I bought Blazer for $8.97, then a couple months later around $9.50.
It has been a few years since then, and the price of ammo everywhere had gone up quite a bit between 2008 and 2012. Not sure what the ammo prices were a few months ago, because I'm pretty well set in that regard. But I haven't ever known walmart to rapidly increase their price on ammo. I can't say with certainty, but if their prices have gone up, it is probably because their wholesale cost has gone up.