The older MF combine have very little value around me here in Iowa. I see MF 750,760,850,and 860 selling for scrap iron price. If some one needs the Perkins motor some times they may sell for a little more.
Just saw a MF 860 Gray cab sell a few weeks ago at auction. It had a 6 x 30 corn head and a 20 foot grain platform. The machine only had 1900 hours on it. The original owner was selling it. The combine was in really good shape. The owner swore the machine had never set outside. It looked like that too. Still shiny. Whole thing brought $3500. I saw it being cut up a few days later when I went back to get some things. I asked a local combine salvage yard owner why he did not buy it. He told me he could hardly give MF combine parts away.
I do not know of any still being used around me. There are some of the newer rotary ones around but none of the old cylinder walker ones anymore.