If your car has an immobiliser it will be very expensive as each key is unique to each car due to the chip inside of the key.
One quote from mitsubishi for my key was £100($150).
If no immobilse, relatively cheap £15($20)
Edit:
Ok, thanks for the added info. The only place you can get the
chipped key from is the manufacturer, straight from toshiba and pay their extortionate prices. Give them a call and their gonna need a car number or something.
If you could buy chipped keys anywhere, there wouldnt be much point in the immobiliser,lol.