"The students help one another" was marked as wrong. Should it be added?

There wan so help, but there was rent instead of that

I've never heard this usage of ~주다 before. Many times I've heard a requestor use this form to make a request more polite. (Also, ~보다 when appropriate.) And I can see how this form can be used when speaking in the third-person ("Alice helped Bob"). But in this context is this form common? 저는 저를 도와줬어요. "I helped myself."?