Leviticus 14:21-22

21If the person is poor, he must bring one young male sheep. And he must bring a tenth of an ephah of flour (about 2 litres) mixed with oil. And he must give a cup of olive oil. The priest must lift them to the Lord.

22The person must also bring two birds. They must be doves or pigeons. These will be his gift. One bird is for a sin offering and the other one is for a burnt offering.