apply payments solution

[hexxabubba]

I'm looking for a simple demo that can populate invoice line items once they are paid. For example; there are 4 ine items @ $10 per, and a payment of $50 or $30 comes in; I need it to apply to line items as paid and show balance. I think the running balanvce is easy enough but populating line items is a lady canine.,...Help....