Hi! I had that problem too and couldn't find any cheats but this one really works! At the end of it I had over a million simoleons!
1.Right first you have to log into the party boat for neighbours.
2.Go back to your house and open the furniture store tab.
3.Then go to the social tab.
4.I have 7 neighbours so find the item that has the highest amount of neighbours you can afford.
5. Fill your whole house with as many of that item as you can (they cost nothing by the way)
6. Then go to the ... tab and click on the Facebook icon.
7. Log out of Facebook so you have 0 neighbours.
8. Then go back to your house that you filled with the social furniture and sell it all.
9. Depending on what item you put in your house the more money you get for them
10. Once you have sold them all you just have to log back into the party boat again and repeat the whole process again! Hope this helped!