Ask HN: Simple CRUD app with free datastore?

HI HN I want to build a simple CRUD application and deployed to Heroku, but I don't want to pay for the database cost upfront (SQL). Any suggestions where I can store the data for free for now?

EDIT: One way I thought of is to find a free SQL hosting site with limited storage, then constantly make a dump elsewhere. That way I can preserve my app without exceeding the capacity.