Leviticus 12:6, 8

“And when the days of her purifying are completed, whether for a son or for a daughter, she shall bring to the priest at the entrance of the tent of meeting a lamb a year old for a burnt offering, and a pigeon or a turtledove for a sin offering

And if she cannot afford a lamb, then she shall take two turtledoves or two pigeons, one for a burnt offering and the other for a sin offering. And the priest shall make atonement for her, and she shall be clean.”