The biggest costs are going to be the building (rent and refurb) etc and employees if you have any. These most important factors are highly dependent on your location and who you know. You may have friends who will help you setup/work for free. You may know someone with unused space. What kind of location do you want? and what do you think you need/where are the customers? Go find a similar location and either straight up ask people using the buildings or find a "to let" sign and call the vendor/estate agent.