The object of the game is to buy a car and a villa in a maximum short period of time. Also, I guess, the objective is to get yourself in the hall of fame - to be recorded there you must have a rating sufficient for that. You are recorded as a hero when you press on the 'Quit' (F10) menu item. Then your current game will end.
The Bank: Loans
Player can make a loan or increase his/her loan amount in the bank at any time at discretion of player. On carrying out that transaction player is immediately charged 10% interest on his loan.
At the end of each month, on "white crow day" players are charged 10% to 25% interest (the longer you don't repay your debt - the more the interest is) on their loan amount unless it's less than 100 coins. If you want to completely change your financial policy for next month then on that day you can repay your loan in full and deposit money under your name.
The Bank: Deposits
Players can open an account or add to it on "white crow day" only. On that day all happy owners of deposits calculate their dividends at the rate 2.5% to 5% per month (depending on how long you have not withdrawn your deposit - the longer - the more the percent is). You can withdraw your deposit or its portion at any time. (With the exception of situations when you want to pay the Business or Mail Cards - keep cash for that).