I want to establish a paid public WiFi system. Here is my model of how it will work:
I will install a public WiFi in my apartment. Using the WiFi system is paid but, voluntary. Those who pay me a monthly cost will be able to access the WiFi. Those who don't pay cannot access the Wifi. Now, I cannot set one password and provide it only to those people who pay money as there is always a chance that the password will leak out to others who have not paid.
So, what is a solid security system so that only who have paid money can access the WiFi?