The driving force of this game is the Market. This was the second feature, after influence, that I implemented, and is very simple despite having the most effect over the way you play the game.

When you start a new game, a price is generated for every item in the game, and every country having it's own price.

The base price of the item is provided by the item's initial dictionary, and then adjusted for every country depending on fertilities.

If the country has zero fertility, the price will be 100% of the base price.

"Normal" fertility (100%), the price will be 75% of the base price.

"Advanced" fertility (200%), the price will be 50% of the base price.

"Expert" fertility (300%), the price will be 25% of the base price.

If the item doesn't have a fertility, then the item will be 100% of the base price. (Basically anything refined, and manufactured)

If you are loading a game, the price of every item in every country is part of the save file and will be the same as when you saved.

Buying/Selling

You can trade on the market fairly easily, just beware of the 5% markup on buying any item.
Example:

Something you can sell for $100, will cost you $105 to buy.

Building Auto-Buy

If a building has need for an item as part of it's recipe, it will automatically buy it from the local market. Currently there is no mark-up, but in the next version of the game (likely 0.0.1.1) there will be a 50% markup. This is to encourage players to start at the beginning of the production chain rather than jumping in at the end and buying everything you need.

The auto-buy can be detrimental if you are not ready for it, and there is no way to turn a building's production off without changing the production item, or demolishing the building.

Manager Selling

If you decide to hire a manager to auto-sell goods for you, they will do so everyday. Anything that doesn't fit into the warehouse will be sold. (More on Managers in a later Dev Diary.)

Daily Market Movement

Everyday, every item has a market price movement. The percentages vary greatly depending on your "New Game Options".

The base of the equation is:

current price x (random number between -1.1 and +1.2)

The market is always slightly skewed to trend upwards.

To save on memory, this is done for each item, and then multiplied out for each country.

So for example:

Let's say we have a watch for $1000

Argentina Price: $593

Egypt Price: $1042

Germany Price: $1244

Every day the market moves, and in this case it says that watches need to go up 0.5%

Argentina Price: 593 x 1.005 = 596

Egypt Price: 1042 x 1.005 = 1047

Germany Price: 1244 x 1.005 = 1250

Market Flux

Every day there is a possibility for a large market flux (beyond the low daily percentage movements). The frequency is determined by your "New Game Settings".

The base settings are as follows:

Every day there is a 10% chance that there will be a market flux. A market flux is just a large jump of any item or an entire market.

Of that 10% there is a 90% chance only 1 item in 1 country will be effected:

"The Price of potatoes in Australia have gone down to 25% of their value."

or

"The Price of Gold Ore in South Africa has risen 300%"

This gives the player the chance to chase that market flux and take advantage if they want. Go buy that dip, or sell in a high market.

The remaining 10% is that every item in 1 country will be effected:

"The market of Italy has fallen to 75% of its value"

or

"The market of Turkey has gone up 200% of its value"

Again, this allows the player to chase after the market and take advantage.

Market Sensitivity

Again, based on what you choose when you start a new game, the market will also face sensitivity based on the actions of the player. (Automated or manual)

Basically, this is just the law of supply and demand. If you keep selling tons of diamonds everyday, there is going to be too much supply, and the value is going to go down.

Alternatively, if you are buying 6000 tons of coal every day to supply your coal power plant, the coal is going to be more scarce, and the price is going to rise.

So be careful where you set up shop, and where you buy and sell your goods as you could be doing damage to the local economy.

Upcoming:

DD8: Library

DD9: Research

DD10: Managers

DD11: News

DD12: ???