This is one of the most interesting things I found, I have to give props for to Soggy Paws for putting this diagram together. It really helps you understand that feeding a good quality food is very important.
http://soggypaws.com/Documents/youcandobetter.pdf
There's some little secrets out there and there's always a way to save a little money. There's a few manufacturers that have Frequent Flyer Programs (Orijen, Acana, Canidae, Natural Balance, Fromm, etc)
Another good article to read is..
Articles Information - Pet Nutrition - Everything You Ever Needed to Know About Dog Food