I was wondering if there was around a hosting as those that have existed for years for PHP that would give the opportunity to publish many Ruby and Rails applications and not as Heroku that forces a single application for dyno.
In classical hosting PHP I can create a folder, upload some files in php and navigate them through links.
You can something like that on some Web hosting?
For small projects, Heroku is really the best deal. Their free tier does everything you'd need for something that's occasionally used and doesn't have a lot of scaling issues. You are restricted to one application per "dyno", per account.
For anything more demanding it's not hard to set up a hosting environment on a VPS provider. Although it takes some additional knowledge, you'll be able to set up and configure a web server using a tool like Passenger and manage your own instances. For $10/mo. you can have a very capable server instance that will handle way more than a $7/mo. dyno can manage. Even the $5/mo. server from a provider like Digital Ocean is a fantastic deal.
PHP's fire and forget method of hosting is convenient, but it's actually a lot more work in the long haul compared to an efficient workflow based around Rails and Passenger.
For example, using Capistrano and a version control system like Git you can make changes, test locally, package up into a commit and deploy on your server within minutes. It's basically effortless once you get it working.