How much time does the user need to digest what’s on the screen before showing a modal box?

I'm designing a feature that would show a modal box indicating the amount of virtual money the user has. This is triggered just after the user decides to log in (assuming they have virtual money).

My questions are:

• How long does the user need to digest what's on the screen after login in until the modal box is shown to the user?
• What would be on the screen that point in an account summary?