Coins are the 'free' currency in CityVille. You earn these through the basic mechanics of the game. The number of coins that you currently have are indicated in the top left-hand corner of the screen. You can buy more coins using your own real money by clicking on the 'Add Coins and Cash' button. Every player starts the game with 7,000 Coins to get them started, and you can see when you are earning them if you notice Coins drifting out from buildings and crops. Click on them to bank the Coins immediately.
This is the 'premium' currency in CityVille. The game itself is free, so Zynga make their money by selling City Cash, which is needed for certain aspects of the game. With City Cash, you can buy exclusive items, hire workers for your community buildings, reduce waiting time and get items that otherwise can only be received as gifts.
You can play CityVille without ever buying Cash, but you will not experience everything that CityVille has to offer and will eventually hit its limit.
The amount of City Cash that you currently have is indicated in the top left-hand corner of the screen. You can purchase more City Cash by clicking on the 'Add Coins and Cash' button.
You start the game with 5 City Cash. You can get more, for free, by levelling up - normally 1 per level. Sometimes you will see notifications in game to complete surveys or take part in offers to get City Cash - only respond to these if they are presented to you in game, do not do so if they are anywhere else or from an untrusted source. If none of these options are enough, and the chances are that they won't be, you will have to buy more City Cash with your own money.
Purchasing Coins and Cash
You can buy more Coins and City Cash by clicking on the 'Add Coins and Cash' button below the currency icons. These have to be bought using real money, and the transactions can be processed using Facebook Credits, PayPal or a Credit/Debit card.
Cheats for Free Cash and Free Coins
Don't even bother following any links that promise you free cash and free coins, especially if you have to hand over your account details. Cash and Coins can only be provided by Zynga in in the ways outlined above. There are no cheats, hacks etc... To cheat your way to free dosh.