There are two types of cat litter boxes: manual and automatic. These two categories refer to different cleaning methods. Automatic boxes are, as the name suggests, self-cleaning, whereas manual ones require user labor. Automatic boxes are often more expensive than manual boxes but require far less user effort.
These two categories are not a firmly divided as one might think. There is a wide ranging spectrum in both automatic boxes and manual boxes. Top of the line automatic cat litter boxes, such as the Litter Robot, are completely self sufficient and will even flush the waste by itself. Other automatic boxes are merely mechanized versions of top-of-the-line manual boxes.
Manual boxes have a wide range as well. Old fashioned manual boxes were nothing more than a plastic tray filled with litter. These trays were messy and required a lot of effort on the part of the cat owner. They required scooping waste and dumping the litter. This process was messy and unsanitary and often resulted in disastrous cat litter spills. Trust me, there is nothing worse than a litter box cleaning gone bad.
High level manual boxes have intricate raking systems and interchangeable trays. Many of these systems resemble automatic systems, with the only difference being that the mechanized cleaning systems are powered by a human hand and not a battery. For the frugal pet owner, these high end manual ones are a great way to improve sanitation and ease of use without spending hundreds of dollars.
Litter boxes have come a long way since their origins as glorified sand boxes. One thing to remember is that quality litter is just as important as a quality litter box, especially for odor control. Do a quick search on the Internet and you will be surprised at the incredible deals you can find on cat litter boxes.