Go to the store and purchase the most expensive thing that you can afford.then place it.after you place it go back to the store and purchase that item again.(The game will still let you purchase it even if you can't afford it).buy as many as you want.then sell all of the things you bought,keep doing this until you have a lot of money.
If you have an item at home and it's from the store and it's in the storage buy something first before you take that item out of storage. Put the item in your house. Then go to storage and click on the item from the store and put it in your house. After that go back to the buying section and select buy on the item that is highlighted. Then it will charge you the same amount of money that the item is that you took out of storage.
First you go into furniture or build mode and buy what you can afford thats the most money. Then put that into storage. Then keep buying it again and again until you can't buy anymore or until you don't want to.(If you don't have enough room in storage then put them all over your house. Then go into the inventory and sell them all unless you want to keep them. Just to let you know once you sell all your items don't do it again unless you have the right amount of money. (I used the wall flat-screen) I hope this helps you.
Buy the same object over and over till you have no more money left once your money reaches to zero keep buying tht same product don't click on none other product stay on the same product once you think you have lots of that same item go to remov e mode the delete all those products when all deleted yu will have more money than you did b4 hope it works http://www.youtube.com/watch?v=bOIKC7DmSjM