Never Die (Requires Memory Card):
'Save' the game when you start the mission and keep saving at the end of your turn if none of your men have been killed. If your men are killed during the aliens turn abort the game and reload the 'Saved' game and do something different so your men don't die on the Aliens turn. Keep doing this through the levels until your mission is over.

Save Money:
Transfer ALL of your scientists and engineers to another base 1-2 hours before the end of the month. Doing this will mean they won't get paid as they are in transit.