The cost of a man cave varies so much that it is impossible to find out how much yours will cost at first. You need to decide what you need to do. The simple necessities like floors, insulation, and walls will be your initial cost.
Most people end up paying around $7500 for their garage man cave, but this isn't including any high-end additions such as pool tables and entertainment systems. So these are additional costs you need to add in yourself.