I would also say, Purina One for a cheaper food and JazzysMom idea for gravy. If you want a better food that makes gravy, I've read a lot about Merricks making gravy when you add water. I think it was Wilderness Blend, but it might be all of Merricks foods.
How much does Jack eat? I guess the reason I ask is that once I stopped to figure out just how little Ruby really eats (1 - 1.25 cups per day), the cost vs. the benefit of good food (switched her from Eukanuba, which the breeder had her on, to Innova Evo - Red Meat, no grain) kind of made my decision. Even with a small bag, it takes over a month to finish the whole bag.
Another benefit was Ruby was never a great eater and I have to make sure she eats enough to keep weight on as she is super active. Once I switched to better food, she gets super excited when dinner is getting ready and she gobbles it down…and I've actually trained her to sing for her dinner (which she would have never done with her old food).