set by
To save or reserve something, especially money, for future use. A noun or pronoun can be used between "set" and "by." If you can set by even $100 a month, it will go a long way toward paying off the loan. Don't throw away all that scrap metal—we can set it by for our next project.
set by
Put aside for future use, as in She had shelves and shelves of cans set by for some imagined food emergency. [Late 1500s] Also see set aside, def. 1; set store by.
set by
v. To reserve something for future use: It is wise to set food and money by in case of a future emergency.