How can one catch the real "piso fare deals" from airlines? Felt like I'm not so good at it even though I frequently check their notifications through email or FB ads. Do they really exist?

Subscribe from their newsletter po. Then, when they piso fares or any promo you'll be one of the many customers who'll receive the info. :) I just did that :) You can also try Air Asia and sign up in their BIG Membership, no fees it's just a membership so you'd be informed ahead of time about their deals. One more benefit of this is that, you'll be prioritized when you book because they will give all their members 1 day ahead priority booking vs regular clients (if ever they have piso fares) :)