So I found this all on
Sensor Tower about the estimaed values of each of the apps... Personally found it really interesting.
To calculate there value they use
-User Estimates
-User Activity
-International Reach
-Revenue Estimates
-Some Secret soruce
As of 12th of Jan 2014 they are:
GraalOnline Classic+ $2,991,930
GraalOnline Era+ $4,718,970
GraalOnline Zone $45,750