To Gain and to Give: Hilchot Tzedakah, Day 16
It was mentioned that ma’aser is taken from money received as a gift. There is a dispute among the poskim whether ma’aser is taken from non-monetary gifts, and if so how the ma’aser is calculated. A Rov should be consulted.
צדקה ומשפט פ"ה הערה כ"ז, אמרי צדקה ע' 133