I have had good experiences running several low traffic web apps (written in Clojure + Compojure + Clojurescript) on one Digital Ocean instance. Right now I am running a ton of stuff on one small Azure instance, getting perhaps just a few hundred thousand HTTP requests per day. But, a $5/month Digital Ocean VPS would probably handle all of your hobby sites.

I am looking to migrate a few of my hobby projects to the Heroku $7/month tier and try that for a few months as a test.

I am happy with their new pricing scheme - seems fair all around.