Pump for drip irrigation

I am interested in purchasing a pump that can be used for drip irrigation of plants from a home cistern. Pump needs to automatically turn itself off if water in cistern is too low, and would like it to run via a timer (can buy separtely) about once a week for about an hour. This would be very small volume – perhaps 50 – 75 gallons per week. Need a pump that can tolerate low loads. Thanks.