PHPCs are Public Health Preparedness Clinics. In the time of national needs like the Novel Coronavirus (or COVID-19 or 2019-nCoV) outbreak, these clinics are activated to provide subsidized treatment, investigations, and medications.

From the people who brought you MaskGoWhere website, they have also brought you the website to identify the PHPC around Singapore.
https://www.flugowhere.gov.sg/
It is very easy to use. You can search the PHPCs by postal code, street name or you can just search them by the clinic name.
As of this writing, there are 811 PHPCs. Do note that for clinics that are under the PHPC scheme, they will have a decal as shown below.

If you are curious how much you are going to pay in these clinics, here is the answer.
If you are diagnosed by the doctor to have a respiratory illness (e.g. common cold), you would enjoy subsidised consultation and treatment as follows:
- Singaporean and Permanent Residents would pay a flat subsidised rate of $10
- Pioneer Generation (PG) and Merdeka Generation (MG) seniors would pay a lower rate of $5
- Public Assistance (PA) cardholders need not pay
GST will be fully absorbed by the Government.
The cost of consultation, medication and investigations provided at each visit to treat your respiratory illness will be covered under this fee. The doctor will prescribe the appropriate treatment for your respiratory illness, including the medications for the expected duration of your illness.
So, there is no reason not to go to the clinic if you are feeling unwell with those symptoms described above.
Stay safe, everyone! And remember to wash your hands frequently and to wear a mask if you are feeling unwell (thanks to CCS, I am now more aware of the status we are in).