i recently sold BeachProperties(.).net for 100$ on DNWE if it was the .com easy high four figures if not five
so that should give you an idea of price difference between .com and .net my personal thoughts on .net is to stay away unless you got some killer one word.
Without specifics, there is no "max" nor "min" price on domain names, regardless of extension. Certain words will be strong throughout, though value expectations should differ on how well it works with the extension and demand for it.