Water coolers are paid for in a variety of ways. Some of the watercooler units are purchased outright and then bottles of water are paid for separately. Other times, the with water cooler rental, the unit is rented and there is a plan for the number of bottles to be supplied each month. Bottleless water coolers are generally rented, and some companies ask for long-term contracts which may last several years. Most companies prefer bottleless water companies to offer month-to-month contracts.