同学,你缺的是一本全面的词典。
《韦氏高阶英汉双解词典》
put by
[phrasal verb]
put (something) by or put by (something) chiefly British
: to save (money) for a later time存(钱)
She has put some money by [=put aside] for emergencies.
她存了些钱以备不时之需。
所以你的句子中,enough 是代词,足够的钱之类,put by 过去分词作后置定语,for her fare 作 put by 的状语,我觉得理解为目的状语或方面状语都可以。