Ammo is hard to find. Well its hard to find at local shops. It's not impossible. I walked in a Turners and the ammo shelves are fairly bare. Yeah there is some ammo on the shelf but its a miniscule amount. A few people walking inand buying the max allowed will blow through their stock.
I order my ammo online. Yeah it's not exactly cheap like the way it was but I just live with it. All you can do is try to find the cheapest price you can afford and buy it or save till you can. As far as Walmart if I can grab a box of something if they have I when I am there I buy it. I have purchased ammo from private party but those prices rival onlin prices so I buy online.