I had a go at answering a new player question on Starting Character Wealth and Equipment in Ars Magica games on Rpg.StackExchange.
In Ars Magica, 5th edition, there seems to be no indication at all of the equipment and resources a character can have. There is just a note reading that any equipment is OK if you can justify it.
How many initial vis can be that in 5th edition? Books? Also how many swords or arcs for a companion or grog?
The short version is to write down the gear and possessions which seem thematic and reasonable for the character’s story and haggle for specific or tricky things; that said there is a huge difference between magical and non-magical related gear and resources as all magical resources are controlled by Virtues and Flaws.
If you’re interested have a read at https://rpg.stackexchange.com/questions/109762/initial-resources-for-a-character