What type of puppy food is best for my German Shepherd puppy?

I have spent several hours researching all different types of dog food. I am getting my puppy in two weeks and he is going to be 8 weeks old. I have read things from people saying Iams is okay for a German Shepherd puppy and others say its terrible. I have read quite a bit about Royal Canin for German Shepherds and it really does sound like an amazing food. My problem is that it also is quite costly. About 60 dollars for a thirty pound bag. I dont even know how long a 30 lbs bag of puppy food would last my puppy. I am just trying to keep things cost efficient and I want my puppy getting the best things possible.