Assuming Green Beans....
100 g green = about 85 g brown and roasted = about 4-6 cups assuming you get the grind correct the first time.
Getting such a small qty hardly seams worthwhile, its over just as you begin.
Better starting with a sample starter pack from Bean Bay and working your way through them.
I think you get 4 x 500 g lots.
Something to get your teeth into!!