Pet food is a real dilemma: once you feed 'em the fancy stuff, they never want to go back to the cheap stuff. Personally, I never buy the expensive specialty food you can buy from the vet or from pet barns: it's supermarket chow all the way.
However, a while ago I was fretting that I was feeding my cat crappy food. Cats need to eat a meat-based diet high in protein, but my online research revealed that a lot of dry cat foods are bulked out with grains, and a lot of wet cat foods are bulked out with random mystery meat (when a label says "meat by-products", this could mean ground-up bones and sinews, or any mechanically reclaimed goo off the production line) and only contain 'flavours' of the stated main ingredient.
One day I spent a lot of time in the pet food aisle of the supermarket, reading the ingredients lists of the various brands. From this I realised that one of the best-quality brands out there is Nature's Gift. They are Australian made and owned, and they don't add extra hormones, antibiotics, flavour enhancers, colours or preservatives to the food.
For instance, tonight I fed my cat their "Roast Duck" food and the first ingredient listed on the label (that is, the main ingredient) is "Duck", followed by "krill oil" and various vitamins. Whereas a mainstream brand like Whiskas can't make duck the main ingredient and still keep its price point. Whiskas' "Juicy Duck" label will list "Meat and meat by-products including chicken, lamb, beef or pork; duck flavour…"
Of course, Nature's Gift is a premium brand. At $1.13 per 100g tin, I only ever buy it when it's on special… which it is at Woolworths right now! The 100g tins, in flavours including "Real Kangaroo", "Roast Duck", "Chicken in Gravy", "Beef in Gravy" and "Chicken with Pilchards", are 88c each.
Nature's Gift also makes dog food, but that isn't on special, unfortunately.