sir, its humble suggestion to go for a vehicle which is actually your passion. deciding an offroad according to the budget wont take you anywhere.
enthusiast usually go for a restoration but needs patience of different level. in a low budget you can get the following vehicles but not in excellent condition.
Partially restored in basic working condition::
CJ5 - 2 to 3 lacks these are usually available in karachi
CJ7 - 3 to 5 lacks
Fj40- in auction condition 200K to 300K
Fj40 - Partially restored any where from 300K to 500K
Potohar - around 300K
Willeys - not in working condition with a diesel engine may be around 300K