Before CNC, a turntable and a dividing head were tools a shop couldn't get along without at least one, often one per mill (or drill-press). When CNC grew up and became today's standard/common machine in a shop, the need for turntables and dividing heads went out-of-fashion, or at least were not needed. So all those tools flooded the market, and the "sale price" didn't seem to have anything to do with the original, or even today's new, price. So offer what you think it's worth to you and see what happens. If it's a large shop, you may have to pay at least scrap value, as they may have it/them in inventory and will have to write it off on the tax return.
I do not have a CNC mill, so I am quite pleased to have 3 sizes of rotary tables and 1 dividing head (that needs a crane to lift!!), all aquired for less than $100 total.
Take care.
Brian Lawson, Bothwell, Ontario.