What is an inexpensive dog food that is good for my puppy?

My 8 month old puppy has been on Science Diet for most of her life. We went to Petsmart and a Bil-Jac rep was trying to push that brand on me telling me how much better it is than science diet. Well, when I let her try some last night, she absolutely loved it. I've been looking on different websites and now on yahoo answers to see what people's opinions are on this brand of dog food and it hasn't been good. Most everyone recommends very exepnsive brands because they don't have fillers in them. I wanted to switch her to a cheaper dog food but scared that she won't get the adequate nutrition she needs. Does anyone know of a good puppy food that's not so expensive that would be good for my eight pound mini schnauzer mix?