Transport billing in asp using c#

Question

hi friends,

  I am doing a small project on transport department.

 for that i need to have billing section.  Here the transport fee will be constant
Fox example transport fee =10000 for a student.

  so the student has the facility to pay the fee in installments. so for the first installment he paid 4 thousand. then the remaining fee  6000 has to be stored in the database.

  and when he pays the fee again in the second installment then the money has to be deducted from the remaining balance fee(6000).

  so every time the balance fee has to be stored and also should be displayed when necessary..

REGDNO :	04331A1209
TRANSPORT FEE:	4000
BALANCE AMOUNT	6000
SUBMIT AMOUNT