You need to become a Master of Mercantile. To do this, you must reach the 3rd Age, build 500 Cargo Warehouses (allowing you to trade 5,000,000 resources every 3 ticks), Market, Spaceport and Space Dock then gain 20 skill points in Mercantile.

You will then be able to trade with 100% efficiency, buying and selling without loss.

While there are many ways to gain those 20 points, I normally wait until the 3rd age, and I have access to 200 oil wells, to fund my skill. When you buy and sell on the market, you have a small chance to gain a skill point, if you exceed the minimum trade necessary. The minimum trade is shown, at the bottom of the Market Tab.

Wait until food is cheap (0.30 to 0.35) then buy and sell the minimum amount. Keep a careful eye out for a skill rise, because you will need to raise your trade size when you do. I use copy and paste to input the trade size myself, as it saves a lot of typing....

Eventually you make the 20th level.



I’d probably avoid trading food, given the need to build silos (and de construct excess houses). Low cash means you can be a little picky buying and selling. I would buy Wood and Iron at, or close to 0.80 then sell when it starts to drop in value (hopefully above 1.20).

Do this twice, and you will more than double your resources. Do it 10 times, and you will have 30 times what you started with.

At some point, you will have excess resources, and be unable to buy fast enough, so you have to buy and sell and less efficient points. Perhaps buy any time its less than 0.85 and sell when more then 1.10

I find that resources are much more likely to hover and hit 0.8 then maintain a high of 1.20 so it is easier to buy cheap then sell. If you should have 30 million iron, you need to start selling early, at perhaps 1.10 or even 1.05

If you are a plus player, it takes 2h 31m to sell 30 million resources.

At some point, you will have excess gold, and nothing to buy. Add oil to your buy/sell options.

When to purchase units I leave to you as a matter of personal strategy. Maintain a strong, low worth & high power defence. If you are losing to attacks, it's time to spend big.