Advice needed for bookkeeping application design

I'm working on a Django web application that offers the users the possibility to buy courses. To do this, each user has a wallet that they fund with money, which they can use for the available products.

My uncertainty lies with the way I should keep track of all these transactions and o开发者_C百科f each user's balance. I imagine that there should be a site account with its own wallet and a payment processor account with its own wallet. I do record each transaction both ways, but I don't know what the balance of the payment processor account should be, if I should fund it constantly and what not.

I hope my explanation makes sense.

The best advice would be write your own one. It does sound simple with a Transactions object keeping track of expenses and income.

Asking 'specific' questions once you start with the design of the application would get you better answers.