In the previous Mishnah we learned that when a woman brings cash into the marriage, the husband records in the kesubah the amount plus fifty percent of its value, since he is able to earn a profit with the money. Our Mishnah also deals with a woman who agreed to bring him cash, and it adds two points: the rate of the increase in a small sum, and the obligation of the kuppah.
The fifty percent increase on cash:
Even a single silver sela is recorded in the kesubah with the fifty percent increase: a sela consists of four dinarim, and with the addition of fifty percent - "sela na'aseh shishah dinarim" - a sela becomes six dinarim.
The Mishnah chooses this example in order to teach that the increase applies even to a tiny sum, and not only to large amounts. The previous Mishnah spoke of a woman who brings in a thousand dinarim, with the husband recording fifteen hundred; here we learn that the very same formula applies even to a single sela.
The kuppah:
We also learned that the groom undertakes to give ten dinarim for the kuppah for every hundred dinarim that she brings in as her dowry, whether in cash or in objects. The kuppah is designated for the woman's personal needs - jewelry and perfumes.
How often is the kuppah given?
This is not spelled out in the Mishnah, and it all depends on the local custom: the time of the payment and its frequency are determined accordingly.