Every event has a package that gives you yellow/orange tickets to buy special decorations.  The trick is that if you are short tickets and try to buy the decoration, you can purchase the missing tickets for 200 gold each.  The $5 package will give you 20 tickets, enough for 0.2 large (6x6 +99 Happiness) decorations, meaning you need to buy 5 in total (which you can't do because the value of the packages go up).  The $5 super sale gives you 14,000 gold, enough for 70 tickets or 0.7 large decorations.  If you buy gold and then tickets with the gold, you get 3.5 times more tickets then buying tickets!  From time to time, the balloon will also offer tickets for gold at 20% off.