To be more specific, exempli gratia means "for the sake of example" where gratia is in the ablative case indicating the cause or reason (to answer the question "what is it for?) and exempli is in the genitive case, indicating possession. "for example's sake" would also be acceptable and more colloquial English, though the phrase is seldom written this way in translation because it breaks up the ablative translation of "for the sake/cause of." It's kinda like splitting an infinitive, which also is just fine in English, but is avoided because you don't do it in Latin.

Dorkusmaximusly,
Hyoun