Health care

They don't have state GP's in the same way you register with your local medical centre, Dentists are plentiful but private. Private health care is cheap try a quote from BUPA sister firm Sanitas.. https://www.sanitasexpat.com/ They also have dentists.

State heath care here can be slow like NHS, private GP's cheap about 40-60- Euro.   

Royal Decree-Law of 2019, anyone with an income greater than €18,000 a year should now pay half the cost of the medication. Those who make less than €18,000 will pay up to 40% and pensioners making less than this amount will need to pay 10%, with a maximum monthly payment of €8. 

Pensioners and those in receipt of state welfare with an income of less than €18,000 are free of all prescription payments. This includes children under 18 with 33% disabilities and adults over the age of 18 with over 65% disabilities.

https://www.justlanded.com/english/Spain/Spain-Guide/Health/Pharmacies-in-Spain

Once you have a health card, it allows any pharmacy to provide your medication. I am retired and the cost of my medicines is very reasonable. It can be hard getting an appointment quickly, but in our health centre you can turn up without one and get to see someone if you have an urgent need. It can be a little hard if you have no spanish. To get the health card you need an S1 form from the NHS which means the NHS pays Spain an agreed sum for your health care. I reckon the spanish system is comparable to NHS but I have no experience of the private care in Spain. As holaitsdavid said, there isn't a fixed fee for prescriptions. I pay 10% which for some things is less than 1 euro.

Are you retiring to Spain from the UK?  Or somewhere in Europe?  If it is the UK then you will need to apply for an NLV and within the requirements of this visa is health insurance.  Not just any health insurance either. It is advisable to talk to a broker in Spain to ensure you get the correct type of policy. We are going through all this at the moment and the health policies we have been told are ok are never the cheaper ones!  On the flip side you may get one that includes all your medications??