Guys, please pay attention to and read the other threads in the forum.
If you don't have enough gold, it means you don't have enough gold earning power.
You will need at least enough space for 8 Large Habitats. Maximise the space that you have. You will need to replace some Habitats and move buildings around if you don't already have enough space.
First off -- Start breeding Terra and Terra Hybrids.
2) Keep the Dragons you don't need in the Dragonarium, or sell them if you really have to, and store the unused habitats. Replace them with Terra & Terra Hybrids one by one. If you have the Dungeon Habitat offshore, then you will have some free space because you can keep 3 Dark Hybrids in it.
3) Move your Crystals around to maximise the earning capability of each dragon.
By my calculation you should easily be able to collect enough gold for whatever you want to buy within a week -- even if you are at Level 15.
Yes it worked for me, hatched my pure sea just 10 min ago. Both breeding and hatching took 48 hours. I was trying to get poo but because i got pure sea i tried the same combo again, and this time i got a pure Tera.