If a price sounds too good to be true, it probably is. Typically, you get what you pay for, and the cost of the service should never be the main reason for choosing a particular carpet cleaning company. Look at the fine print on ads or when you talk to the company ask them about maximum allowed square footage per area or room.
Remember, you want to use a company that isn’t using harsh chemicals that will harm your family, pets, or carpet. Some chemicals leave a residual behind which can cause rapid re-soiling. This happens when the sticky residual collects the dirt off your shoes like a magnet.