Cats need more nutrients than what are in dog food - taurine for one.
Without taurine, cats will go blind.  A snack or tow of dog food is OK every
once in a while, but not a steady diet of it.

What we do his buy equal amounts of high end cat food (more nutrients, also
expensive) and low end (cats love it, and it's cheaper) and mix the two.
That way we know that they are getting what they like AND what they need.
That way I'm not buying twice as much of the expensive stuff (saving money),
nor feeding them all the cheap stuff and hurting their health.

i feed them Brand name food--but maybe i could feed them cheaper

I've found more expensive dried cat food works out cheaper in the long
run. You need to feed the cats a LOT less of it than  the cheaper
stuff. Takes a bit of getting used to through when I first used IAMS I
filled the bowl and wondered why most of it ended up in the bin. I find
the smallest handful I can make (Or about a third of a mug) is enough
for a meal for my two cats. For example I brought a 1.5kilo bag of
Royal Canin 3 and a half weeks ago and only now am I thinking of
getting another one

I suppose it depends a lot on how often you feed dry.(and the size of
the cat- my Fabulous Furballs are petite)  Normally my cats get one
meal of dry and two of wet and I put some dry down before going to bed
in case they want a snack at night. Then again with my partner in
hospital for the last 9 weeks so they're being left on their own a bit
more (He works from home so normally they would have a slave to refill
the bowl on hand all the time) and they're getting more dry than normal

As for dry dog food the rule is the same as wet dog food, if you
somehow ran out of catfood and the only shop open only had dogfood then
it's better than nothing at all but only as a stopgap until you can get
catfood

Lesley

Slave of the Fabulous Furballs

Cats and dogs have different nutritional requirements, so
you should not feed your cat dog food regularly. It lacks
some of the nutrients cats need and has other stuff that
cats don't need--like carbohydrates, which may play a part
in digestive problems or diabetes.

//Zino