17 Ketubot 6/5-7

(5) One who marries off his daughter plainly [without any stipulation as to dowry] may not give her less than fifty zuz. If [the father] stipulated that [the husband] is to marry her without clothing [as part of her dowry], the husband may not say, "When I bring her into my house I will cover her with my garments." Rather, he must clothe her while she is still in her father's house. Similarly, one who marries off an orphan may not give her less than fifty zuz. And if there is [sufficient means] in the [charity] box [from which she is being provided for], we provide her [with an outfit] in accordance with her honor.

(6) [With regard to] an orphan who was married off by her mother or her brothers with her consent, and they had written [i.e, assigned a dowry] for her a hundred or fifty zuz, when she comes of age she may recover from them whatever is her due. Rabbi Yehudah says, "If [the father] had married off the first daughter, [the dowry should be] given to the second [daughter] in the same manner as he had given to the first." The Sages say, "Sometimes a man was poor and became rich, or was rich and became poor; rather, we appraise the property [the father left], and we give her [her fair share].

(7) If a person entrusts another with money for [to purchase a field or a dowry for] his daughter, and she says, "I trust my [future] husband, [so give me the money]," the trustee must [nevertheless] act in accordance with [set of the instructions] that was entrusted to him. These are the words of Rabbi Meir. Rabbi Yossi says, "And if [what he gives her now] is merely a field which she wants to sell, it is [as though] it is already sold." With regard to what were these words stated? With regard to an adult woman; but with regard to a minor, the actions of a minor are meaningless.