In DragonVale for the Android & iOS devices (iPhone, iPad, etc.), the Liberty Dragon is a limited dragon that is only available around Independence Day (aka 4th of July).
The Liberty Dragon has a base breeding time of 29 hours and 49 minutes, sells for 3,000,000 coins, and earns 1,500,000 XP for successful breeding once you reach level 17.
To breed a Liberty Dragon, you just need to breed a Copper Dragon with an Air Dragon or hybrid that contains the air element.
Need lots of gems at a cheap price? You can actually buy DragonVale gems on Ebay.