Startbonus:
Collections: 600 coins every 8 hours (7200)
For collection times check this.
We can also get up to 600 coins from a quest and 350 coins from each round of Dragon TV.
Dragons:
Wurm #176 costs 965 coins
Mana #540 costs 2390 coins
Pyre Magus #1321 costs 4855 coins
Black Magic #835 costs 10780 coins
Rime Magus #1320 costs 15230 coins