Price of cleaning should be compared with price of new injectors. No new injectors are less than PKR 35K.
Reasons for considering cleaning instead of buying used injectors:
1 Used injectors can also be clogged. One can not acquire optimum performance from the engine with clogged injectors. Optimum performance mean best fuel economy maximum pickup etc.
2 Injectors apparently same can be of different specifications in terms of flow rate & impedance. Therefore one can not be sure about used injectors if they are exactly of the same specifications which are requirement of one's engine. Your old injectors are selected by the manufacturer of the car according to the needs of the engine.
3 Ultrasonic cleaning restores injectors to as new condition. So its wiser to get your old ones cleaned and get them performing as new again instead of buying a set of injectors which could be a mismatch for your car. I've met many who have changed their injectors with kabli ones and have complaints of increased fuel consumption and black smoke from exhaust reason of which is obvious.
