At the start of a scenario you are required to build a stockpile
with no cost.
After you build the required granary you can delete the stockpile
for gold, then build another one for free. Repeat this for quick money.
You can use this trick to get your buildings up early.
Just use the trick, set up a market, and just buy raw materials needed
to purchase buildings and units. Note: Materials in the stockpile
disappear if you delete the building. Take advantage of pausing the game.
Defenses and units will be waiting long before the enemy has a chance