Car wash kits typically include everything you need to clean your vehicle. Car wash soap, wax, interior cleaning solution, microfiber cloths, sponges and a washing mitt are normally included. How long these various products will last really depends on how often you use them and how well you take care of them. You will go through the soap and wax much quicker if you wash your car once a week instead of once a month. Washing mitts and microfiber cloths must be washed out and rinsed whenever they are used. Under normal wear and tear, you should replace them on a yearly basis.
For more info, see How Many Car Washes is Too Many