Yes, quality brand pet food here is more expensive. But store brands and other cheaper brands often have a high ash content, which is not good for the animals and can cause health problems in the long run.
In the States, mine were on Hill's, which is a better quality than Iam's there -- but I converted them to Iam's here, because my vet told me that it is just the opposite here, Iam's is better quality than Hill's.
I guess it comes down to an issue of whether you're stretched to the limit financially here, or you can afford to provide your pet with the best. I'd rather give up a couple of my personal luxuries if it means being able to feed them high-quality food. But for many people down here, personal luxuries aren't even part of the equation.