You need to make a list of what you want in the room. Measure the room and apply some unit prices for labor and material. Drywall, insulation, carpet, paint, doors, trim, electrical wiring, electrical boxes, Lighting etc. If you can do a lot of the work yourself you can save a lot of money. Check Home Depot for prices on the items you need. Some of the work you might have to hire out such as electrical. I would look for a handiman to do the work that you are not capable of doing. Take a little time to do your homework and you might be supprised.
Good Luck.
Good Luck.