Specialty food for my cat, though I'm really considering switching her to a raw diet once we move next month. My friend works at a specialty pet store and says that often feeding your pet a raw diet can cost less than regular food, you just need to know how. She use to get eggs and raw fish more regularly, but I haven't in a while.
I have to feed my dog prescription food that I buy from my vet. He has been eating it for about a year now. Sometimes when money is tighter I have mixed his food with rice to stretch it out a few more days until my next paycheck. He loves when I add rice to his food, but I know it's better for him to eat his prescription food.
I have to feed the cats prescription cat food--my little guy that pees on the toilet has issues and needs a special food. The dogs get a specialty brand dog food--I grab it from the vet's office when I get the cat food. There is no particular reason for the puppies, but it is very convenient for me to grab them all at the same time.
I use Purina One. I used to use Science Diet which is also a good commercial food. Whatever you use, make sure that meat is the number 1 ingredient. Some cheaper dog foods will have mainly fillers. The first item listed in the ingredients is always the item that the product has the most of and it goes down from there.
We used to feed our Mastiff Blue Buffalo, didn't like it because it made him farty. Then we put him on some other designer food (that didn't have chicken in it, turns out he's allergic to chicken) but it turned out that the protein levels were so high his liver was on the brink of shutting down. So now he's on Kirkland Brand (Costco) Premium Adult Dog food (Lamb, no chicken). The ingredients are comparable to the designer dog foods but the protein levels are 22% not 34%. Also it's half as expensive!
We used to feed the outdoor cat store-brand cat food because it was cheaper. (The indoor cat got the Friskies food.) We forgot to pick it up for a while and started feeding her the Friskies and now she refuses to eat the generic stuff.
As for all this, "Oh, you shouldn't feed your pets those foods!" that the natural food commercials spout out... yeah. I refuse to pay that much for food for a cat. The conventional stuff is expensive as it is.
It doesn't have to be expensive to be quality food. I used to use Royal Canin until I realized that. But honestly, find the price range you're comfortable with and then the food your baby likes to eat. The fact that you care about the nutritional value will help you find the right one!
Here's what I used to research my dog food before selecting: