So after some simple data gathering, I’ve discovered the formula for Wiz3’s Magic Missile attribute cost.
3000 * 1.07^(x-1), rounded down, where x is the level of the attribute.
From this, I calculated the total cost for leveling the attribute to 100 to be 37,144,940 silvers.
Boy is that some money sink.
Edit:
Of course, since it’s exponential, at level 80, you would have spent only ~26% of the total cost (9,567,152 silvers) so you have to decide if the last 20 levels is worth the silvers.
Edit2:
The formula for Meteor attribute cost is similar:
5000 * 1.07^(x-1), rounded down, where x is the level of the attribute.
Edit 3:
Apparently, almost any skill that follows an exponential growth does by a factor of 1.07. This has been true for all other elementalist skills I’ve tested so far:
intial cost * 1.07^(x-1), rounded down, where x is the level of the attribute.
Hail (4000), Prominence (4000), Frost Cloud (6000) and Meteor (5000), where the numbers in parentheses are the initial cost.