Fin, Fur & Feather in Ashland, Ohio (I-71 Exit 186) generally has a decent selection of powder. I son't know what they have right now, but I bought a couple of 8lb kegs of Promo ($87.90 each). Their selection of primers is very good and I've never seen the shelves empty ($27-$30).
Their Claybuster wads are under $10 and shot is <$45/25lb. If you're in the area, it's worth a sidetrip.
My other favorite dealer, Bottom Dollar Gun & Archery in Washington Courthouse, Ohio) is expecting more powder in January.