Income is described as the total amount of money a player can earn by doing their job. The expected income of a player is at least $900 every five minutes, allowing you to buy a shipment of AK-47s at least once every hour.
A formula is used to determine how much a player's income is. Remember, players are expected to make at least $900 every five minutes. This doesn't mean players are only capable earning exactly $900 every minutes. Higher risk brings higher reward, and supply and demand will really account for how much you can potentially make.
The formula used takes the salary (as determined by the salary formula) of a player and takes extra income they might be earning from doing their job and determines the average amount they will earn every five minutes. The max amount of money that job can earn performing other acts is then taken, such as mugging for a maximum of $250, or healing for a maximum of $100, and assume the player is earning this income at least once every five minutes. That amount is then taken away from their salary. Citizens are excluded from this step, since their services are not commonly used. Kidnapping is also excluded. When two extra sources of income are equal in max value and are the highest available sources of income, both are subtracted.
For example, to determine a Medic's salary, this formula is used: ( (AK-47 Shipment Cost) / 12 ) - 100 = $650.
Another example is a gangster. They earn money from mugging, extortion, kidnapping and theft. It is assumed that a player cannot do all of these at once, and kidnapping is not considered, so only the $250 mug amount and $250 extortion amounts are subtracted: ( (AK-47 Shipment Cost) / 12 ) - 250 - 250 = $250
This leaves the the player under the quota of hourly income, but assuming the player is earning that extra income three times in five minutes, the player will reach the $900 expected salary, if not exceed it. This means that competition or lack of demand will determine how much a player will actually earn, for better or for worse. This is especially true for dangerous jobs. The reward often tremendously exceeds the expected $900 salary, but the player risks dying and losing their stuff.
Continuing our examples from above:
( (AK-47 Shipment Cost) / 12 ) - 100 + (100*3) = $950
( (AK-47 Shipment Cost) / 12 ) - 250 - 250 + (500*3) = $1750
As you can see, the gangster has the potential to earn significantly more money, however they are at a much higher risk by doing so. This counteracts the near-double income.