The Cheapest Trick in the Book!

[Atreidi]

Ok, here is a question for the pros and to the experienced...
What is the cheapest trick in the book?
When you want to win and want to win FAST without caring for the "quality" or "fun" of the game, what do you do?
What do you consider to be the cheapest easiest way to win?
*without cheating ofcourse*
Is it massing out one unit?
Spell Spam?
Do share!
(On your average game, small/big/huge what is the cheapest trick regardless of settings?