How do I level Scion with no budget?

I would like to know the fastest way to level up a scion until level 30 for example. Let's assume in a SSF situation.

Thanks

It generally depends on what type of build you are running, what type of damage nodes you are taking and what leveling skills also synergize off of the nodes you are taking.

The one universal piece of advice is to always choose the Quicksilver flask as your quest reward, and possibly pick up a second one. Also use a movement skill, like level 1 flame dash, when you have stable mana via passives or mana flasks.