Events

Some events you could use.

CoinsAddToPurseEvent » Event that triggers when a player receives coins in their purse. Event is not cancellable, you can get the added coins and the player parsed as string (could be player's name or player's UUID, if you are gonna use that you need to check if it's a UUID o a name).

CoinsRemoveFromPurseEvent » Event that triggers when a player loses coins from their purse (triggered on any kind of transction not only purse death events). Event is not cancellable, you can get the removed coins and the player parsed as string (could be player's name or player's UUID, if you are gonna use that you need to check if it's a UUID o a name).

CustomEntityKillCoinsEvent » Event triggered when a custom entity is killed and the player receives coins from it. Event is cancellable and you can get the player, entity and coins from this event.

EntityKillCoinsEvent » Event triggered when an entity is killed and the player receives coins from it. Event is cancellable and you can get the player, entity and coins from this event.

PiggyBankClickEvent » Event triggered when a bank is opened thru a piggy bank. Event is cancellable and you can get the player from this event, as well as verify if it is a shared bank or not if you have the only-one-bank enabled in config.

PurseDeathEvent » Event triggered when a player loses coins on a death event. Event is cancellable and you can get the player and taken coins from this event.

RandomCoinsTalismanTrigger » Event triggered when a player receives coins from a random coins talisman. Event is cancellable and you can get the given coins and player.

SharedBankCreateEvent » Event triggered when a player creates a shared bank. You can get the shared bank id as well as the player from this event. This event is cancellable.

SharedBankDeleteEvent » Event triggered when a player deletes a shared bank. You can get the shared bank id and player from this event. The event is cancellable.

Bank Transactions Events » BankDepositEvent, BankWithdrawEvent, SharedBankDepositEvent, SharedBankWithdrawEvent | Names are pretty self explinatory.