Source : Free On-Line Dictionary of Computing

TANSTAAFL
     
        /tan'stah-fl/ (From Robert Heinlein's classic "The
        Moon is a Harsh Mistress") "There Ain't No Such Thing As A
        Free Lunch".
     
        Often invoked when someone is balking at the prospect of using
        an unpleasantly {heavyweight} technique, or at the poor
        quality of some piece of {free software}, or at the
        {signal-to-noise ratio} of unmoderated {Usenet} newsgroups.
        "What? Don't tell me I have to implement a {database} back end
        to get my address book program to work!"  "Well, TANSTAAFL you
        know."  This phrase owes some of its popularity to the high
        concentration of science-fiction fans and political
        libertarians in hackerdom.
     
        [{Jargon File}]
     
        (1995-02-28)