To get money quickly and efficiently at low levels before you have many dragons at high levels that give you heaps of money, try breeding a plant and lightning dragon together for a cactus dragon. It takes 30 mins to create the egg and another 30 mins for it to be ready to hatch. It sells for 100 000 dragoncash. If you were to do this for a whole day you'd get 2 400 000 dragoncash in 24 hrs. As you get higher there are probably better dragons to do this with but this one gives a decent amount of money for a short period of time.