Leviticus 5:7
If, however, he cannot afford a lamb, he may bring to the LORD as restitution for his sin two turtledoves or two young pigeons--one as a sin offering and the other as a burnt offering.

Leviticus 14:30
Then he must sacrifice one of the turtledoves or young pigeons, whichever he can afford,

Leviticus 14:32
This is the law for someone who has a skin disease and cannot afford the cost of his cleansing."

Leviticus 15:15
The priest is to sacrifice them, one as a sin offering and the other as a burnt offering. In this way the priest will make atonement for the man before the LORD because of his discharge.