Well, there is a chart for different types of numbers 3, 2 and 1 digit. Its a very self explanatory chart issued by motor excise and taxation dept Islamabad. A good and honest agent will have it and will show it to you. There are no extra charges for normal 3 digit no. Good 3 digit no starts from rs 8000 and multiplies for 2 and 1 digit up to more than rs. 200, 000. Depends on how much crazy you can be for a particular no. All this money is deposited on a challan to the bank and agent has nothing to do with it. I can give you details of a very main stream, good and honest agent if you're intrested.!! ?