In the Core rules table back on P 21
Pures may learn their base to 50th, and Open/Closed of their realm to 20th level.
Hybrids may learn their base to 50th, Open Lists of their realms to 20th, and closed to 10th
Semis may learn their base to 50th, and Open lists of their realm to 10th level
Non casters may learn open lists of their realm to 5th level.
Using the expanded, then full list availability options opens that up further, but changes the base costs. Using uption 2.5 for instance:
A magician uses the "pure" column
Magician base lists to 50th level for 1/* rank.
Open Essence Lists to 20th level for 1/* per rank.
Open Essence lists 21-50 level for 2/* per rank.
Closed Essence lists 1-20 level for 1/* per rank.
Closed Essence lists 21-50 level for 3/* per rank.
Etc. etc. etc. down the Pure column.
(note, the magician "pure" cost for spell lists is 1/*, the red portions are not allowed in the core rule, but are allowed using this option, but they increase the cost from 1/* to 2/* and 3/* respectively)
You just identify the column that corresponds to the profession of the character, cross reference it to the list portion or ranks you are trying to learn, and that gives you the cost per rank on the table.
Be wary. . .especially with "Other base lists", "Other realm" and "Other realm base lists".