We can host our wordpress application free on Heroku. Here is the few steps. Heroku gives us:
1 dyno Postgresql DB (10.000 rows limited, we can switch to 10 mb MySql if needed.) Custom domain setting is possible. These are enough for hosting.
Setup There 2 popular templates. First one is simple, second one is a little complex but performs better.
If we do not have performanse issues, we can choose first one. At our OS git and heroku cli should be installed.