Originally Posted by maalloc

Exactly. For months now, 3HK has had this "special" that gives dozens of GB for HK$33, valid for 30 days.
Your first step would be to buy a SIM card at a physical location and upload your passport picture. Then you're all set for 30 days.

Later on, you can re-use the same +852 number (for up to 6 months IIRC, could be 12) and add another HK$33 to your 3HK wallet. Use this amount in your 3HK wallet to buy the "special" again (it's a 2-step process that can be confusing at first), and you are set for another 30 days.

I haven't been in HK for a few weeks so I don't know it the offer is still available in May '23, but I can give you an update when I arrive next week if needed. I also haven't tried to buy the package again within the validity period, since I never use more than 1 GB per day anyway, so I can't tell for sure whether you can use it 2x within 30 days, if that's what you are asking.