St. Bernard is a very large working dog breed. Saint Bernard was originally breed for rescue but many times they proved their loyalty and build an image as guard dog.
The average size of Saint Bernard is in between 65 to 100 kg. They are good watch dog and guard dog as well but at the same time they are bit slow dog as well. They are very tolerance with children and never heart them.
Here is list of available St. Bernard breeders in India. Each Breeder / Kennel have their own page, you can go through their pages and can talk to them directly about buying Saint Bernard puppies. Click on given link for more information on St. Bernard puppies for sale.