Ask HN: Casual/Easy Hosted Database?

I like to use Heroku for hobby web servers, but those are ephemeral (disk gets cleared on deploy)

I'd like to pair it with the cheapest, simplest managed persistence I can get. No real requirements around performance or scaling, don't really care what DB it is; I'd use JSON files or SQLite if I had a persistent file system. I don't want to mess with any more configuration than necessary, I just want a place to put data where it won't disappear on me.

Any suggestions?