Hello & welcome to the sight!
Depending on condition ( a picture of the inside & outside front/sides/back would help) between $200-500 maybe (unrestored) meaning no hugh dents, good trim, no rust/missing paint, complete-ness ( all of it's shelves & coinmech & lightup sign) running condition (gets cold ( not just the fans are running) steel/painted COKE sign lower end, lightup sign higher end of the price scale. oh, and if it has it's lock & key that's always a big plus too.
well that's my opinion anyway.