If you can and finish the drywall yourself you can do it for around $80.00 to $100.00 per room depending on size of room and how much drywall you need.
Hanging the drywall is pretty easy and you can buy a drywall lift for around $200.00 which made it easy for me to hang some drywall in my own house.
In total I spent around $1,200.00 including the drywall, drywall mud, drywall tape, and drywall lift.
If you have a pro hang and finish the drywall you may be looking at $2,000.00 to $3,000.00 for a complete drywall job including the finishing of the drywall.
It depends on the size of house you have and if you want just part of the house done or if you want the entire house done with new drywall.