Host multiple application on same server using nginx reverse proxy. This is highly cost saving technique for test servers or low request servers.
Note: Host server OS assume to be Ubuntu 18.04, below all config directory and command will on this linux flavour. You may use the diffent flavour thus config path and cmd may change. However core idea will be the same.
Step 1: As you need a single machine, where you install nginx on port 80.
And run your any language server say we have 4 websites as one in Ruby on Rails, second on nodejs and some are on php and golang. I started all application using their application server on different port as:
Ruby On Rails using Unicon: 3000 as => ror.server.com / rorserver.com