Are you sure about that?
I'm pretty sure that there is a base setup cost for each model printed.... For example, printing a single one of my turrets would cost 5 euros, while if I make a single file with 25 turrets it costs less than 10 euros...
I think if you were to make a single stl file with 4 or 8 copies of the chainsaw, they would end up costing less than 5 euros each!
Not that I'm complaining, mind you, it's that this way you could add a little more markup for yourself and get lower prices, too!