Where do you host your PostgreSQL?

The hosting of the data can get expensive. For larger projects, you will most likely end up paying for the database (unless you host the database on your own machine).

I'm looking for some DBaaS options for PostgreSQL. Ideally pay-for-what-you-use services (no fixed costs for a plan) with great scalability options.

By the research I've done, I'm aware of:

• Heroku PostgreSQL, which offers pretty limited free tier, like 10k records or so.
• Google Cloud SQL or Amazon RDS, including their free tier for a year.
• Self-hosting on $6 DigitalOcean droplet or similar services.

What are some of the most cost-effective PostgreSQL hosting solutions that you use and would recommend?