The price of a used Caterpillar excavator 312D2 can vary depending on several factors, such as the condition of sheil, the age, the hours of operation, the location, and the seller.  Generally speaking, the price of a used Caterpillar excavator 312D2 can range from around $18,000 to $27,000 USD.  It's important to thoroughly inspect the machine and verify its history before making a purchase to ensure you are getting a fair price for the equipment.