How much is a 69 ford bronco worth?

My brother bought a 69 ford bronco last year off a farm in the valley and were trying to see if anyone knows what it's worth. We had some people tell us that it wasn't worth alot and then try to buy it off of him, and it's not for sell. Can any one help please. He's 17 and i'm 14 so we don't know to much about trucks. It runs good.