I don’t think it’s bad at all that people use Heroku to host their small projects. You can handle more than one concurrent request on Heroku, if you use Node. And if you’re willing to use a cloud database service like MongoLab, each of your apps can get 240MB of Mongo database for free. For my non-monetized side projects, I would much prefer to have an extra $30 each month than the flexibility of a VPS.