koding.com has a free VM running Ubuntu. The specs are pretty good, 1 gig memory for example. They have a terminal online you can access through their website, or use SSH. The VM will go to sleep approximately 20 minutes after you log out. The reason is to discourage users from running live production code on the VM. The VM resides behind a proxy. Running web servers that only speak HTTP (port 80) should work just fine, but I think you'll get into a lot of trouble whenever you want to work directly with other ports. Many mind-like alternatives offer similar setups. Good luck!
GridPane: This free VPS management tool lets you host up to 3 websites on a single server without paying a dime. It comes with a built-in SSL certificate and offers low priority ticket support. In fact, it is one of the few SaaS hosting control panel with support for One-Click WordPress Staging. All in all, Gridpane is a robust VPS management platform with support for all unmanaged VPS hosting companies that offer VPS servers with Ubuntu 16.04 LTS.
I was on a mission to look for new VPS hosting for our new website. It was between Bluehost, Dreamhost, and InMotion Hosting. After a chat with Adam, it is clear that InMotion Hosting is the best choice for us because of the outstanding support. I want to let you and your department know that Adam is doing an outstanding job for your company. I will refer my friends to you guys."
VPS hosting is essentially a virtual slice of a server which you can scale to your own needs with your own dedicated resources. At Hostek, we never over-sell server capacity, in fact we operate in a highly available server environment and, on top of that, we’ll transfer you to another available server space in the event that your host server goes down.
A VPS runs its own copy of an operating system (OS), and customers may have superuser-level access to that operating system instance, so they can install almost any software that runs on that OS. For many purposes they are functionally equivalent to a dedicated physical server, and being software-defined, are able to be much more easily created and configured. They are priced much lower than an equivalent physical server. However, as they share the underlying physical hardware with other VPSes, performance may be lower, depending on the workload of any other executing virtual machines.