As far as I know, there is just one cheat in YoVille, but that cheat is a major one. I am sure you are wondering how people can afford all the very expensive items in theor appartments, if you look at the pictures of my apartment, you will see that I have plants and furniture that are worth many 1000's of coins. The reason I could get all of those plants and flowers, rugs and furniture is cloning of items. You might have read that cloning of items in YoVille is not possible, there are a few websites that claim it can't be done, but that is not true. There is a glitch in the interface that will allow you to clone any item. The process for cloning is hard to describe in words as the process requires a specific technique, but I will explain how it works and refer you to a video that shows the process very clearly.
Cloning items takes advantage of the game interface and the potential for slow down in the game. Start out by editing the room where you want a cloned item, make sure your item tray is empty and grab the item you want to clone and place it in the tray as the only item. Now, start clicking the item very quickly, while moving the mouse left and right as if you want to move the item along the tray. The fade out effect in YoVille will allow you to grab the item twice and dropping one copy in another cell in the tray. You will now be able to grab one of the two items and place anywhere in your room, and you can repeat and clone the item over and over. This is how I was able to get so many plants in my apartment, and also get enough sand carpets to make a beach. All for the price of just the original item.