What’s the best cheapest method of metering water at farm level?

Dear friends, I am Ruby and I have a query about the water meters. Last season we had a drought in our area and so we have decided to monitor and manage the water supply at farm level and at domestic level efficiently. Local government officers have installed some water meter at domestic level. But I am interested in knowing how the water at farm level can be metered? What’s the best cheapest method of metering water at farm level? Is there any cheap device which can be used for monitoring discharge from bore well?