I have a water leak at the foundation of the house. What is the cheapest adn easiest way to fix it? Thanks.?

This past month, my husband and I received a $400 water bill. They suggest we have a leak [well duh]. Our home warranty is not going to cover it, so we priced plumbers. They are outrageous. What is the easiest way to fix it on our own? Need help asap. The home warranty will not cover. The leak is not in the foundation, it is just right by the foundation. It's outside the house.. Our water meter is in our alley..