You can often hear this expression among french people.
Literal translation: That doesn’t eat any bread!
Actual Meaning: That doesn’t cost much OR There’s no harm in trying !
So why not trying something because it doesn’t cost much and entails no risk! 😉
Ex: Téléphone à ton médecin, ça ne mange pas de pain!
Notice: In spoken French, “ne” in a negative sentence is often ignored and the “e” of “de” is often swallowed. So you hear /ça mange pas d’pain/ instead of /ça ne mange pas de pain/. Of course, it is not grammatically correct but it is the way native speakers would speak in an informal conversation.