Unless you plan on teaching your cat how to use the toilet like in a popular movie, you will need to purchase a litter box and everything that goes in it. This involves the litter box, the scoop, and the litter. If you have a kitten it is important that the litter box is not so big that they cannot get into it, but on the other hand you need to get a litter box that is big enough for a full grown cat.
What many cat owners may not know is that the litter boxes that have hoods or covers may actually trap foul smelling odors and make your can unwilling to further use the litter box, so it may be a good idea to avoid these altogether.
Another helpful tip is to keep some sort of garbage container next to the litter box so that it will make it easier to scoop the box on a regular basis, just make sure that the container you choose will keep the odor inside the container and out of your room. The last item is of course to find litter that works best for you and your cat. There are many varieties that have odor control and clump better, what you choose is up to your own preferences.