for free

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.