Who is playing a tower event for the first time should read this.
Collectingtimes are explained here.
We start with 200 coins. We can collect 600 coins every 8 hours. So we can get 5600 coins in total. Coins from quest or cinema are not included.
Iceberg Dragon #424 last piece costs 120 coins
Snowman Dragon #259 last piece costs 800 coins
Iceling Dragon #717 last piece costs 1000 coins
Brave Dragon #1023 last piece costs 1500 coins
Arctic Dragon (new) is at the top in the middle