Cost to drywall a house completely would depend on the square footage of the house and if demolition needs to be done beforehand.
If you can get the demolition done before hand and get the walls gutted down to the wall studs then it will be cheaper.
Drywall will likely cost around $1,000.00 or a little more for a 1,000 square foot house and it could take the drywall company around a day or 2 too get the drywall put up so you could be looking at $1,000.00 in labor costs to hang and finish the drywall.
I would call a drywall or remodeling contractor near you and get a quote.