The cheapest automatic litter box in this index costs $229. Over four years it is more expensive than the $699 one. That is not a trick of accounting; it is how consumable-funded hardware works, and it is the most useful thing we can tell you about this category.
The three recurring costs
Bags or liners. Either ordinary kitchen bags at roughly $30 a year, or a proprietary roll, film cartridge or disposable tray at anywhere from $90 to $220 a year.
Carbon filters. Between $35 and $60 a year depending on the model and how honest you are about replacing them on schedule. Skipping them is the most common cause of a box that "stopped working" on odor.
Litter itself. We leave this out of our comparisons because it is roughly constant across boxes and depends on your cat, not your hardware. Budget $150 to $300 a year per cat on top of everything below.
Why cheap boxes get expensive
A low sticker price funded by mandatory consumables is a deliberate business model, not an accident. The PetSafe ScoopFree is the clearest case in this index: $229 to buy, roughly $220 a year in crystal trays.
By year two you have spent $669. By year four, $1,109 — more than a Litter-Robot 4, which costs $699 and about $90 a year to run, landing at $1,059 over the same period.
The crossover point is what matters. If you plan to keep the box under two years, the cheap one wins. Past three years it does not.
How to read our cost tables
Every review on this site carries a five-year cost table showing purchase price plus running costs, with the three nearest alternatives alongside it. The numbers come from the same database as the specs, so they update when the specs do.
We price consumables at the cheapest genuine source. Third-party consumables are usually cheaper and are the leading cause of sealing and sensor errors on the boxes that use them, so we do not price them in.
We do not include electricity. These units draw a few dollars a year and it is noise in the comparison.
The cheapest way to own one
Buy a box that takes ordinary kitchen bags. This is worth more than any discount you will find at checkout.
Replace filters on schedule rather than on smell. A degraded filter costs you the odor performance you paid for, and by the time you notice it you have been living with it for weeks.
Keep it. These boxes are mechanically simple and the good ones have excellent parts availability. Total cost per year falls every year you keep the same unit running.
The short version
Price the box over four years, not at checkout. Bag type is the variable that decides the answer.