You can go to Luke's All Natural (
Dry Dog Food Sampler Pack - Luke's All Natural Pet Food ) and they will put together a sample pack of different super-premium kibbles for you.
You can specify what you are interested in. I wanted them to select all life stages foods, since at the time I had both a puppy and an adult and wanted them to eat the same food. They stuffed the box full, even throwing in a few sample sizes of treats and shampoo. Once I settled on the brand and type of food, I just used the rest as treats.