If you are at Clark Airport, never get a taxi unless you are as rich as Manny Pacquiao.
Taxi fare to SM Clark (less than 10 kms from the airport) would cost 400-500 pesos depending on the generosity of the taxi driver.
What you should do is to walk up to the gate of the airport (200 meters). Ask any airport security guard as to where you could get a jeep to SM Clark. Once you're in SM Clark, you can get a bus to Subic, Angeles City, Manila or to any places in Luzon.
If you're going to Clark Airport, just take a jeep (destination is "Main Gate") from SM Clark. Just tell the jeepney driver that you want to go to Clark Airport.
Your fare? 10 pesos only.
Say NO to taxi drivers who think you are a millionaire just because you don't speak Tagalog according to their accent.
Linkback:
https://tubagbohol.mikeligalig.com/index.php?topic=28075.0