They're selling it for 20% over wholesale... Pretty common for feed stores, they are just selling a lot of it to make their money, instead of selling it like box stores do...smaller quantities with huge mark ups.
My wholesaler buys direct from the mill, and charges me 10% over to bring it to me. He makes 10% for doing nothing but being closer to the mill than me, and he already brings me my order anyway... Win/win.
If you happen to live close to a Purina mill, or a ADM mill, or whatever mill, you can buy direct. Mills are located pretty much all over the US. It's easier for them to bring the products to the mill, and mill it, rather than truck the finished product all over the country. I have a Purina mill about 45 miles from me, but they don't mill Mazuri, they mill the LabDiet Rat Chow, which I don't like...