Two words: Selling crystals.

Seriously. I've made 500k in the past week from occasionally going online and doing Elger Quests. I don't finish the quest if I'm required to spend more then 5,000mp and I don't sell my crystals for anything less then 5,000mp. I spent all my money a couple months ago changing one of my pets and I've made 6 million since then--working on my goal of changing all of my pets to the desired look.