The Mishna in Kiddushin (1:1) outlines a machlokes regarding the minimum amount of money necessary to effect kiddushin (i.e. create a marriage).
According to Beis Hillel, the amount of money (or equivalent goods or services) required is a perutah. A perutah is the smallest amount of money with buying power; so I understand philosophically that the Torah is saying one way to execute a marriage is with a symbolic transaction that minimally looks like a valid business one. The one-perutah requirement is similar to people with salaries (or rents) of "one dollar per year."
Beis Shammai, however, requires a dinar (or equivalent goods or services), which is quite a bit more. What's the source for the dinar requirement (once it's not "anything with buying power", where do we set the bar?), and do we know how Beis Shammai may have viewed kiddushin accordingly?