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 14:10
On the eighth day he is to bring two unblemished male lambs, an unblemished ewe lamb a year old, a grain offering of three-tenths of an ephah of fine flour mixed with olive oil, and one log of olive oil.

Leviticus 14:22
and two turtledoves or two young pigeons, whichever he can afford, one to be a sin offering and the other a burnt offering.