Source : Free On-Line Dictionary of Computing

funny money
     
        Notional units of computing time and/or storage handed to
        students at the beginning of a computer course; also called
        "play money" or "purple money" (in implicit opposition to real
        or "green" money).
     
        In New Zealand and Germany the odd usage "paper money" has
        been recorded; in Germany, the particularly amusing synonym
        "transfer ruble" commemorates the funny money used for trade
        between COMECON countries back when the Soviet Bloc still
        existed.
     
        When your funny money ran out, your account froze and you
        needed to go to a professor to get more.  Fortunately, the
        plunging cost of {time-sharing} cycles has made this less
        common.  The amounts allocated were almost invariably too
        small, even for the non-hackers who wanted to slide by with
        minimum work.  In extreme cases, the practice led to
        small-scale black markets in bootlegged computer accounts.  By
        extension, phantom money or quantity tickets of any kind used
        as a resource-allocation hack within a system.
     
        [{Jargon File}]