Firstly, click here to Play Farmville
Credits: PaperJam
Follow the steps on the images. Click for bigger view
the money saves. Be warned though, if the game refreshed, the item disappears so only stop when you are done.
Try on a cheap item first! Once you are confident, do it on the most expensive item you can afford.
Most expensive building is the VILLA.
Note: if you screw it up, you will lose both the money you paid to buy the building and the building itself. So make sure you test on a cheap item first! I have managed to get 1 million from just 400k.