My guess for tractor values down here in SC is $400 to $800 for a running WC and $800 to $1200 for a running WD depending on shape (not restored, mind you). You see them sold for more - and less - but that's just a ballpark figure.
Saw a highly-modified one not too long back with a "stroked" D17 gas engine in it putting out more than 100 hp for pulling. Had the original tranny and rear end. He pulled in 3rd (road gear), believe it or not.
Good old tractor, the hand brakes are kinda aggravating and no live pto but it will work itself forever. Roger Welsch's great books are all pretty much concerned with WC's. Made from 1933 to 1948 and tested at 25.45 belt hp on distillate and 29.93 hp on gasoline. One of these days when I get a little $$ I'm going to buy one ...!