Yes sand will work just fine for use as kitty or cat litter and the cat will be able to use the litter box without a problem even with the use of sand.
The kitty litter though helps to absorb the odors somewhat and absorb any urine as well which makes the cleanup of the kitty litter box less messy.
I have used sand myself for my cats litter box when I ran out of kitty litter and didn't have any more money at the time to buy more cat litter.
The cat was a little apprehensive at using the cat litter box at first because he was unfamiliar with the sand and was used to the clay cat litter.
But eventually after a few hours he got used to it and used the litter box without a problem with the sand.
So if you cannot afford to use cat litter you buy in the stores then the sand or some regular dirt will work just fine for the cat litter box.