Calculating Totals Depending On Type

I have a database in which 3 different areas can receive a payment. Prepay Amount, After Hours Charge, Previous Balance. Each one of these payments has 3 different payment types.... cash, credit, check. Now, when a cashier takes a payment, they have to choose whether it's cash, credit, or check, and they can feasibly enter payments into all 3 fields. The question I have, is how can I do a balance sheet whereas everything is broken down into cash, check, and credit for all 3 payment categories. Then I will need it to add up the cash, credit, and check for a grand total.

For example:

Transaction 1 - Prepay -$20 check Balance -$10 check
Transaction 2 - Prepay -$10 cash After Hours -$20 cash
Transaction 3 - After Hours -$20 credit Balance -$30 credit
Transaction 4 - Prepay -$30 check After Hours -$20 check
Transaction 5 - Prepay - $40 cash Balance -$30 cash

How do I get the following output?

Prepay-------$100 (Cash $50 Check $50 Credit $ 0)
After Hours---$60 ((Cash $20 Check $20 Credit $20)
Balance-------$70 (Cash $30 Check $10 Credit $30)
--------------------------------------------------------
Total ---------$230 = $100 + $80 + $50

This is a basic example......each cashier handles about 100 customers per day. I don't want the cashiers to have to tab through a bunch of fields, and the cash/check/credit are on drop down lists.