On the food calculator sticky, go to the last post and find the scoring chart. You can figure out the score for the food you are feeding. Then at the bottom of the post someone has worked out the scores for many popular foods.
Another good site is
www.dogfoodanalysis.com
Once you develop a short list of products you might like to try, go to the websites for those products. Almost every one will have a store locator to find something near you. Go there and they will usually have small, free sample bags. I walked out with dozens of bags, maybe 6 foods to try, before laying out the big $$$ to buy a bag of something my dog won't even eat.
If all else fails you can order dogfood online. Some have free shipping.