Which type of termite control is the most efficient in term of price in my case
The most cost-effective methods of termite control, in descending order:


Live where it's too cold for termites - $
Treat the soil around the perimeter of your house with termiticide once every 5-10 years - $
Build a physical termite barrier around your house out of metal, fine sand, cementboard, or some other material that termites can't eat or pass through, leaving inspection strips along the perimeter of the foundation - $
Build the structure and finish materials of your house out of non-wood materials - $$$


...


Wait until your house has a major termite infestation and needs to be fumigated and major structural and finish materials replaced - $$$$$$$$$$$$$$$$$$$