Anytime it is not possible to do Yi'ud (marriage of the master or his servant to the maidservant) the sale of a Jewish maidservant is not valid. (1)
Anytime it is not possible for a Jewish servant to subtract from the sale price when he buys his freedom the sale is not valid. (2)
Reish Lakish says that Beis Shamai learns out Kidushei Kesef from a Jewish maidservant; just as a maidservant may not be sold for less than a Dinar so too Kidushei Kesef may not be for less than a Dinar.
Rava says that the reason why Beis Shamai holds that Kidushei Kesef may not be less than a Dinar is so that Jewish women will not be Hefker. (3)
It is a Machlokes if a Perutah is 1/8 of an Italian Isur or1/6 of an Italian Isur.
There are 1536 Perutos in two Sela'im. (4)
If a person is Mekadesh a woman with a date even if worth much less than a Perutah it is a Safek Kidushin because maybe it is worth a Perutah in a different place.
A woman is not believed if she testifies that a woman is an Eshes Ish.
If a woman says that she was captured but she is Tehorah she is believed even if two witnesses are aware that she was captured but had not yet testified.
Abaye and Rava hold that if two witnesses are aware that a woman accepted Kidushin she is regarded as an Eshes Ish even though the witnesses are far away and had not testified, while R. Chisda argues.
Rav gave Makas Mardus to someone who was Mekadesh a woman in the market or was Mekadesh with Bi'ah or without first discussing the Shiduch.
Rav gave Makas Mardus to someone who was Mevatel a Get or notified witnesses that he did not give the Get willingly. (5)
Rav gave Makas Mardus to someone who pained a Shali'ach of the Rabanan or remained in excommunication for thirty days and to someone who lived in the same house as his mother-in-law.
Neharda'a says that Rav only gave Makas Mardus to someone who was Mekadesh with Bi'ah without Shiduchin and some say even with Shiduchin because it is Pritzus.
If someone is Mekadesh with something that is worth less than a Shaveh Perutah and she find out later that there was a Perutah wrapped inside even though she did not throw it down it is not a Kidushin. (6)
If someone gives money to a woman as a Pikadon and prior to the Nesinah he says you are Mekudeshes to me with this money it is a valid Kidushin.
If he says you are Mekudeshes to me with this money after he already gave the money to her as a Pikadon if she says yes it is a Kidushin but if she is silent it is not a Kidushin. (7)
A BIT MORE
1. Therefore she may not be sold to a relative who is forbidden to marry her.
2. A servant may buy his freedom and when he does so he subtracts from the purchase price in accordance with the length of his servitude and therefore a servant may not be bought for a mere Perutah because it is impossible to subtract from a Perutah.
3. Beis Shamai agrees that Min ha'Torah a Kidushin of a Perutah is valid; however the Rabanan decreed that a Dinar is required so that women will not be Hefker.
4. This teaches us how much a person must distance himself from an Aveirah. If someone benefits from Hekdesh the amount of only one Perutah he must bring an Asham which costs two Sela'im.
5. If he authorized a Shali'ach to give a Get to his wife and than he subsequently was Mevatel the Shelichus he is punished with Makas Mardus because of the concern that the Shali'ach will give the Get anyway and people will not be aware that the Get is Batel. A person also is punished with Makas Mardus is he was forced by Beis Din to give a Get and he gave notification to witnesses that he is not giving the Get willingly.
6. Because her silence after she had already received the money is not regarded as an acceptance of the Kidushin.
7. Because her silence after she had already received the money is not regarded as an acceptance of the Kidushin.
SHAVEH PERUTAH B'MADAI
If a person is Mekadesh a woman with a date even if worth much less than a Perutah it is a Safek Kidushin because maybe it is worth a Perutah in a different place. The Rambam says that if he was Mekadesh her with a cooked dish or with a vegetable that will not last very long if it is not worth a Perutah in the place of the Kidushin it is not a valid Kidushin at all even if it is worth a Perutah in another place because it will not last long enough to be taken to another place. The Maharik says that this Sevara only applies to a cooked dish or vegetables because there is no possibility at all that it will last long enough to be taken anywhere but a product such as a date that can be dried out and last a long time is a Kidushei Safek even if it is not worth a Perutah since if it is dried it can last a long time. (Kesef Mishneh)
THREE TYPES OF KIDUSHIN
If someone is Mekadesh a woman with Bi'ah it is a Kidushin Min ha'Torah and so too a Kidushin with a Shtar is a Kidushin Min ha'Torah, but Kidushei Kesef is mi'Divrei Sofrim. Even though this is true m'Ikar ha'Din however the Minhag of Klal Yisrael is to be Mekadesh a woman only with Kesef or Shtar but not with Bi'ah. If someone is Mekadesh a woman with Bi'ah he is punished with Makas Mardus so that Klal Yisrael will not act with Pritzus even though the Kidushin is a valid Kidushin. The same is true with regards to someone who is Mekadesh a woman without Shiduchin or in the marketplace; even though it is a valid Kidushin he is punished with Makas Mardus so that it will not lead to Znus and cause women to be akin to the Kedeishah that is mentioned in the Torah.