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!
It provides you with even more options, including root access, access to Apache and PHP.ini (modification of PHP variables), and much more. You can also install an SSL certificate, and all software program types. In short, you get more freedom in terms of administering and configuring your server, without the hassle of managing any physical hardware.
Amazon EC2 is a web service that provides secure, resizable compute capacity in the cloud. It is designed to make web-scale cloud computing easier for developers. You can use Amazon EC2 for a variety of applications, including websites and web applications, development and test environments, and even back-up and recovery scenarios. Amazon EC2 offers a wide selection of instance types with varying combinations of CPU, memory, storage, and networking capacity that you can use to meet the unique needs of your applications.
Unmetered hosting is generally offered with no limit on the amount of data-transferred on a fixed bandwidth line. Usually, unmetered hosting is offered with 10 Mbit/s, 100 Mbit/s or 1000 Mbit/s (with some as high as 10Gbit/s). This means that the customer is theoretically able to use ~3 TB on 10 Mbit/s or up to ~300 TB on a 1000 Mbit/s line per month, although in practice the values will be significantly less. In a virtual private server, this will be shared bandwidth and a fair usage policy should be involved. Unlimited hosting is also commonly marketed but generally limited by acceptable usage policies and terms of service. Offers of unlimited disk space and bandwidth are always false due to cost, carrier capacities and technological boundaries.[3]