Is it permissible for a married woman, who has her own income and whose money is commingled with her husband's in one purse, to intend to give charity or provide for her family from her own money when spending?

It is permissible to dispose of a woman's private property and to give charity from it. The best charity is that given to relatives. As for spending from the husband's money for charity, it is permissible to give a small amount that is customarily overlooked without his permission. Anything beyond that is not permissible except with his permission.