Shulchan Arukh, Orach Chayim 306:6שולחן ערוך, אורח חיים ש״ו:ו׳
6. One may discuss Mitzvah matters such as estimating the costs of a Mitzvah, pledge money to charity, supervise the needs of the community, discuss matchmaking for children, (hiring a teacher to) teach them books and a trade. One may only ask if he is willing to be hired but it is prohibited to hire him or discuss a price. RAMA: Some say that in places where the one who reads the Torah offers a Mi She’beirach and pledges charity, it is forbidden to state the amount he intends to give, (Or Zaruah) but the custom is to be lenient because one may pledge charity.
Shulchan Arukh, Orach Chayim 323:4שולחן ערוך, אורח חיים שכ״ג:ד׳
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