Leviticus 12:8; Leviticus 14:21

And if she cannot afford a lamb, then she shall take xtwo turtledoves or two pigeons,1 yone for a burnt offering and the other for a sin offering. zAnd the priest shall make atonement for her, and she shall be clean.

21 But nif he is poor and cannot afford so much, then he shall take one male lamb for a guilt offering hto be waved, to make atonement for him, and a tenth of an ephah of fine flour mixed with oil for a grain offering, and a log of oil;