'72 Blazer 4 parts - how much is it worth???

[YBSTUK]

i've got a friend that has a 1972 4x4 Blazer that he's looking to sell. He has no ideas as to what it's worth. i have no pics yet (sorry), but from this description, can anyone help with a "guesstimate" as to how much it might be worth??

4x4 K5 Blazer
6 cyl. (motor supposedly runs - it DOES turn over)
manual (99.9% sure its not an Auto)
no top (someone cut the old one off behind the front seats)
all flat tires
rusty body (side panels are probably gone - hood OK, front Grille OK)
Tailgate rusty, i beleive.
frame looks solid

i know those are kinda vague descriptions, but anyone take a guess as to what it might be worth? it's located in Northern Illinois.