Hmm to calculate how much you must ask, you should calculate the cost of all your computers, the OS licenses, the game licenses, the rent, the electricity, the public gaming spot license cost, the taxes, the life expectation of your hardware before it needs to be replaced, the expected players volume, the necessary personnel with relative salaries and social extras, the share between earnings and reinvestment, and at the end of all that, you can see how much you can ask for 1 hour of LAN gaming without bankrupting after 2 days ;-)