I just bought one for 50 gold then upgraded it for 100 gold
No idea what the upgrade means, just thought the building would look cooler.. It didn't :/
TL
I along with my baby dragons, thank you
Edit(KP) 8-5-2015- New Lower prices
Level 1: 25 Gold, 5 Dragons
Level 2: 70 Gold, 10 Dragons
Level 3: 140 Gold, 20 Dragons
Level 4: 360 Gold, 40 Dragons
Level 5: 1000 Gold, 80 Dragons
Edit(KP) 3-2-2015
Original Holds 1 Dragon - 50 gold
Upgrade Holds 2 Dragons - 100 gold
Upgrade Holds 4 Dragons - 200 gold
Upgrade Holds 10 Dragons - 1,200 gold
Upgrade Holds 25 Dragons - 5,000 gold