Upgrade Your Skills Event

In this event, wild creatures will drop Wishing Bottles. The Wishing Bottles can also also be bought using diamonds.
Wishing bottles can be used to exchange for :

2 Wishing Bottles - 250 gold coins
20 Wishing Bottles - Level 2 scroll ash
40 Wishing Bottles - Level 3 scroll ash

One may be tempted to exchange them as soon as you see the gift box flashing, but hold off.
If you recall, I made a previous post that compares the values of the scrolls and ashes at different levels : http://sislandec.blogspot.com/2010/08/value-of-scrolls-and-ashes.html

So 20 wishing bottles get you an equivalent of 1.67 synthesis runes.
40 wishing bottles get you an equivalent of 13.67 synthesis runes.
So I strongly suggest that you wait for 40 wishing bottles, where each bottle gets you 4 times more value.