One who marries a woman using a ring and who says to her “I sanctify you to me according to the laws of Moses and Israel” actually has married the woman through monetary transaction. (The ring is worth money.) The Sages ruled that there is no possibility of “buying” a woman with something worth less than a perutah (approximately a single shekel). Therefore, if a man sanctifies a woman with a ring worth less than a shekel, the sanctification is not valid and she is still considered single. Many doubts have been expressed and many details have been discussed on the topic of “a man purchasing a woman through monetary transaction.” Thus, for example, one of the Babylonian sages, Rava, voiced his doubts in the study hall: is the sanctification valid if a man says to his beloved “I sanctify half of you with half a perutah and the other half of you with another half perutah“? What are the issues under debate? On one hand, half a perutah does not purchase, as we noted above, so the marriage is not valid. On the other hand, since he immediately adds a second half perutah for the second half of the woman (which still is single), it might be considered as sanctification by a whole perutah.
The sage continued and asked: what is the rule if under the chuppah he tells her “I sanctify half of you with a perutah and the other half of you with an additional perutah“? What is the rule if he says “I sanctify half of you with a perutah today, and I will sanctify the other half of you with a perutah tomorrow”? What is the rule if he says to her “I sanctify both halves of you with a single perutah” — can a woman be sanctified in halves? Another sage, Rav Papa, asked: what is the rule if a man says to a woman “I give you a perutah for your daughter and for your cow “? Does this mean he gives a perutah for the daughter and intends to acquire the cow by dragging it (and so the sanctification is valid, since it was affected by a perutah) or that he gave half a perutahperutah)? (These questions are not resolved.)
(Babylonian Talmud Tractate Kiddushin 7b)