What's the easiest/cheapest way to create a cloud-based SQL database?

sql database sqlite cloud

For more flexibility, less service lock-in, and cheaper scalability: I would suggest CouchDB (though you would likely still use a hosting service like Cloudant). CouchDB can host your website, and provides a HTTP API for storing data, to which your client-side JavaScript can make REST calls.

sql database sqlite cloud

StackMob has a free package that you can use. You can use the JS SDK to write your HTML5 app and save stuff to the StackMob DB. You can host your HTML5 on StackMob for free and point your own domain to it as well. There is also S3 integration.

Some references: