Manufacture for Free
     Go  to Start a New Manufacturing Job from the list of items. When
the  window  pops  up  asking you how many units you want and how many
engineers,  leave  both values at 0. Just click OK, then quit from the
list  of items to the main menufacturing screen. You selection will be
listed  as  normal  with  0  units,  0 engineers. Now go to change the
values of the manufacturing job and change the number of units to just
1.  This  1  unit will then be manufactured in the same time as normal
but for free, plus it won't use any materials.