Receipt Allocations the Easy Way
One of my clients wanted a simple, inexpensive billing and payment system. The main screen for each student shows a list of what's due:
Then, when they click the "Payment" button to the left of whatever is being paid, they see this:
Advantages of this system
It's very easy to use, and very inexpensive.
Disadvantages of this system
If one check comes in to pay multiple charges, there's nothing in the system to prevent your making a mistake.
For example, let's say the check is for $80.
There's nothing to prevent you from allocating $50 to one charge and $50 to another charge - so the users have to be very careful.
This defect is addressed in my full-blown receipt allocations that was done as part of a complete invoicing and accounts receivable system.