for free

adj. [common] Said of a capability of a programming language or hardware
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.