for free
adj. Said of a capability of a programming language or
hardware equipment that is available by its design without needing
cleverness to implement: "In APL, we get the matrix operations for
free." "And owing to the way revisions are stored in this
system, you get revision trees for free." The term usually refers
to a serendipitous feature of doing things a certain way (compare
big win), but it may refer to an intentional but secondary
feature.