How much will it cost to change a workshop into a mother-in-law suite?

I'm thinking about buying a house that has a workshop in the back yard. I don't need the workshop so I was thinking about converting it into a mother-in-law suite. The workshop is maybe a 30 by 20 room which I want to finish (it has insulation but no dry wall) and put a closet and maybe a half bath. Any idea how much all that will cost? How much will it cost to change a workshop into a mother-in-law suite?This depends on how many walls..carpet/tile..types of textures,paints, ligfght fixtures on and on...the quality of the materials/appliances/ammenities ...If you could do all the work yourself you may escape with around 15k..expect 25 to 30k to hire someone to do it..BUT..the first thing I would check before buying the house is to see if you can obtain the local permits to do there first..just ask the building department if that zone can have an out structure for habitation or not