If a woman herself gives Machatzis Hashekel, Should her husband also give for her, or its unnecessary?
Women generally are exempt from Machatzis Hashekel. There is a common custom that the husband gives Machatzis Hashekel on behalf of his wife.
I have never heard of a custom where the woman herself gives the Machatzis Hashekel. Obviously, if she does do so, the husband would be exempt from giving.
However, I fail to understand why introduce new customs, and tamper with the existing Minhag Yisroel, when one such a custom clearly does not exist.