Kiddushin 7 - Cash Flow
If a woman suggests to a man, "Give money to so-and-so and I will thereby become betrothed to you," and the man gives the money as specified and says the formula, the woman becomes betrothed, through the principle of a guarantor. A guarantor of a loan, even though he does not personally receive the benefit, still binds himself to repay. So too she commits herself, in return for the money based on her say-so.
A special man who also never accepts gifts (none today) can marry a woman by giving her the pleasure of accepting her gift.