A UPS inverter is the device inside a UPS that converts the electricity from DC to AC so it can be used for all the devices we need power for today. The price depends on the power rating and on what brand produced it. Prices can be from the mid-ranges all the way to the top.
An Uninterruptable Power Supply (UPS) has another device built into it, which is called an inverter. An inverter does not provide electricity but converts it. The conversion is from Direct Current (DC) to Alternating Current (AC). Batteries produce DC which is useless for our devices today, as most if not all run on AC. The inverter inside a UPS does this important conversion for us so the energy can be consumed.
The price of a UPS inverter depends on its power rating and brand. They can be in an affordable range or can be from a much higher price point.