Advancement in this rule system is handled by XP (might be renamed to Karma). Increasing Attributes and Skills as well as buying Spells costs XP. Attribute and Skill costs are exponential. Spells cost a flat amount.
Most Attributes cost nothing for their basic value (depending on Gender, Metatype, Size and Weight) and give back XP when chosen to be a smaller than their basic value. Doubling a value from its basic value costs the same, regardless of the actual basic value. This ensures that characters with high basic values, like Charisma with Elves and Strength with Trolls are not handicapped.
Skills are are ordered in a 3-tier hierarchy. Buying the highest tier gives a big discount compared to raising all Skills blow that Skill in the tree and raises everything that is below that Skill in the tree to the selected value. Buying lower tiers gives more control but is more expensive. The XP cost are always calculated in difference to the highest value in the upper tiers, so it is possible to select a moderate value in an upper tier and then specialize to a higher value in a lower tier.