-The tax for all vehicles above 1000cc is 1500 i guess, but some other taxes are also included so I don't remember the total amount.
-There is no option of life time token in Sindh, it's available in Punjab though.
-Just go to the Civic centre or an authorised NBP branch, tell me your address and I'd tell you about the nearest branch, you can pay your tax there, without the need of an agent, but try to get a token.