They typically sell in full working condition for about US$400 and can be had for less if you don't mind doing some refurbishing. The question is: what is it going to be used for? If you're trying to calibrate anything more than about a 3.5 digit DMM it's not worthwhile. As a device to spot check a multimeter and determine whether anything major is wrong, it's pretty handy. Only you can decide whether a working unit will be useful, or a broken/out of calibration unit is worth repairing.