It's working the same in 4th ED.
But for a Ghost Master you need an Orichalcum coin, which costs 10.000 silver. It's also really hard to find and summon one in the first place and should first occure when nearing the Warden Circle.
The normal and most common way to increase your circle is to find and pay a master. A Training Pledge should only be an exception.
Btw, instead of heaping a lot of silver, you also can use gold, elemental coins or even gemstones.
In my world we introduced a bank system and got rid of the money exchange costs. It works with the nethermancers spell Grave Message (instead of Internet
), so each bank is always able to check how much money the character currently has.
This is just a simplified system we actually don't put too much thought into. There is no pay rent / tax and there are no adventures involved, where a bank gets robbed or even a player wants to rob one.
But you could do so, if wanted:
Just think of it as an extremely secure building, having some elemental earth in the walls and one or two kaer runes protecting the money.
The Grave Message itself is secured by a changing password and in a world without higher technology, it shouldn't be possible to crack it this easily
The effort to rob the bank is probably higher than the possible income ^^