Cash Book is a very easy to use app to note your cash transaction with your friends. You get notified when you have to collect the given credit money back from your friend. And vice a versa you get notified when you have to return back the debit money taken from your friend as debt. Payment return can be full payment or partial payment. You can easily note it down with each date when it was returned. You can notify your friend through whatsapp by sending the details of transaction and your f