Quiz: Remember the definition of mal de mer?
Worthless, counterfeit, or play money (1938+)
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.