What are you looking for in a "holistic" dog food? What kind of proteins does Penny do well on?
I think Natural Balance and Taste of the Wild are some of the best kibble you can get for a fair, mid-tier price. Around here, 18 pounds of Halo puppy is also about $55, Halo adult is a few bucks cheaper.
28 pounds of Natural Balance or 30 pounds of Taste of the Wild is about the same price as an 18 pound bag of Halo.
It takes my two dogs quite some time to go through that amount of food though (we do occasional raw meals now), so I figure the cost between raw, those previously mentioned kibbles and Orijen 6-fish, which is the priciest kibble that I rotate, doesn't amount to that much in the end for exponentially better quality food than IAMS!