Wally world had sts and AA's for under $50 a flat last year. Hard to say what it will be this year...Gamaliels was the ammo house vendor if I remember right.. their sts's are $59.50 on their site. I don't expect that to change on site..
If I remember correctly a few of the cheaper brands of shells they ran out of for a few days at the grand. Gamelli's (I dont think I spelled it correctly) is the only shell dealer and they had all kinds of shells at all kinds of prices. It did not work like the old Grand where you paid the same price no matter what kind of shells you shot. I think that the overall shell price was a lot cheaper than what they used to charge. And yes there is Wal-Mart and other stores in Sparta. It is not as big a hick town as some people want you to believe. It has a number of real stores. Also St. Louis is only about 50 miles away.
Many were clearly better off to price shop at home and truck the new shells to Sparta last year. Also, reloads allowed again. A careful pre-Sparta shopper can save money. If you are an impulse shell buyer, you are fair agame!
As mentioned above, Walmart had MANY pallets of the major brands of shells, very reasonably priced, they didn't go for the gonads like most of the other businesses in the area did for all their products and services. If you couldn't find something suitable at Wallyworld, then prepare to pay the Gamaliel rate at the shell house.