Found this on FB, posting for everyone's benefit.
Heya is not for everyone. It is only for those who do not mind putting in extra effort to monitor the expiry date for your data plan.
If you can do that, it is $10 for 100GB for 30 days (50GB immediately plus 50GB extra one to three days later) on Singtel which is the best deal. You also get free incoming calls, free incoming SMS, free caller ID, and VOLTE. There are other promotions from time to time, but these features above have been there on Heya since day one.
Note that the retailer should not be overcharging you; new line + port in should cost $10 and not a cent more. The retailer needs to complete a two-step process: Register + Port in (Keep Existing Number), and once that is done, take note of the temporary number and top-up $10 to the temporary number (not your port-in number). This should all be done in a single visit and should take no more than 15 minutes.
You should only buy your plan on the very last day of the expiry if your current plan, as the 30 days expiry starts on the date you purchase the plan. It does not extend the expiry of your current plan. For example, if your current plan expires on 15 August 2023, you should buy your next plan anytime on 15 August 2023; if you purchase it later, you lose the rollover data; if you purchase it earlier, the 30 days starts from the date of your purchase, and not 15 August 2023.
Only sign-ups need to be done physically at a retailer; top-ups can be done online via Lazada or Shopee. The links are all found on the official Heya website.
Please read through the official FAQ on the
https://heya.sg website before signing up.