for oneself; for one's own sake; on one's own account
Expresses doing something for one's own benefit, purpose, or interest. Often used adverbially to modify a verb.
See also: ために
I study for my own sake.
He is saving money for himself.
Means 'self-centered' or 'egocentric'; 自分のために is neutral and simply indicates acting for one's own benefit, without the negative connotation.
Standard kana-mixed spelling; the most common written form.
Kanji spelling using 為; less common but still seen in formal or literary contexts.
Compound of 自分 (self) + の (possessive particle) + 為 (sake, benefit) + に (adverbial particle). The phrase is transparently derived from its components.