The new habitat is on sale but the dragon isn't. 1600 gold. Ouch.
Cartographer dragon is on sale for 480 though. Might bite the bullet and get that one.
Edit(KP) Dragon is now on sale in market 480 gold.
Make sure you are on the most current version of the regular game to see this Dragon.
The Market Description says 4.63/hr, and here is a level breakdown below based on hourly rate.
Lvl 1 & 2 - 4/hr
Lvl 3 - 11/hr
Lvl 4 - 13/hr
Lvl 5 - 15/hr
Lvl 6 - 16/hr
Lvl 7 - 17/hr
Lvl 8 - 19/hr
Lvl 9 - 20/hr
Lvl 10 - 21/hr
Lvl 11 - 22/hr
Lvl 12 - 23/hr
Lvl 13 to 15 - 24/hr
Lvl 15 - 25/hr
18 hours to hatch egg