Leviticus 5:7, 11

And if his means suffice not for a lamb, then he shall bring his trespass-offering for that wherein he hath sinned, two turtle-doves, or two young pigeons, unto Jehovah; one for a sin-offering, and the other for a burnt-offering.

But if his means suffice not for two turtle-doves, or two young pigeons, then he shall bring his oblation for that wherein he hath sinned, the tenth part of an ephah of fine flour for a sin-offering: he shall put no oil upon it, neither shall he put any frankincense thereon; for it is a sin-offering.