Case Plow Value

I know it’s about impossible to give a value of something over the net, but all I need is a ballpark figure. I have a friend who has some equipment that was his dad's who died 10 years ago. He told me if I wanted anything, I had first dibs. He doesn't know much about the stuff. It has been about a year since I looked at any of it. One item is a Case 4 bottom plow. It was missing one coulter I know for sure. I don't remember what the bottoms looked like I think they may have been buried in the leaves. I don't want to rip my friend off and at the same time I don't want to rip myself off. I looked though the old photo ads and the archives here. Would about $175-200 be in the ballpark? I am going to try to buy a few other things at the same time. Thanks.