Number of things you need to consider.
1. Cats have preferences. There is clay or "sand" litter generally, though probably pellet is another type (I'm not switching to find out). Use whichever they prefer and don't mess with it or suffer the consequences.
2. Within those broad types, they have preferences. I used Fresh Step for years, and stopped because they got much dustier. Mine don't like Tidy Cats, and when I tried it they informed me that it was not acceptable. I tried 4 different brands of litters before I settled on Arm & Hammer (or the yellow box if I got the name wrong) as acceptable to both cat and human. For clay litters, I think they're pretty much all the same, so go with the cheapest brand (though I don't use...)
3. If you're lucky, your cat's preferences are vague, so you have more flexibility in brands. If you are unlucky, stick with what they like regardless of cost. If you don't, they may not use the box.
4. Clay litter needs to be replaced every week or two. Sand type will last much longer, typically several months, maybe more with daily scooping. Number of cats will affect that as well.
5. Cats are quite unhappy about a dirty litterbox. The definition of dirty is theirs, not yours. If they consider it too dirty, they won't use it and you'll suffer the consequences.
6. Cats also develop preferences for size and type of litterboxes, and depth of litter. Some like enclosed, some don't. Some want lots of room. Some like higher sides. In general, the bigger the cat, the bigger the box. 12+ lbs you generally need the biggest box. Multiple cats may need larger boxes as well.
7. Multiple cats - rule of thumb is number of cats +1 is the number of boxes you need. Again, depending on the cats you may be able to adjust. My 2 cats require 2 boxes, and are happy with that.
8. Box location matters.
9. Litterbox problems can also indicate a physical problem. If there's a problem with using the litterbox, rule out physical, then you have to dive into the messy world of behavior, box type, box location, and litter type and it is really not easy to sort out (doable, but takes longer).