I've been using Linode for years. You can buy lots of different configurations, but I've been renting a couple of virtual servers (full root access, not just web page hosting) for $5/month per server. You have full access to make the system host as many virtual hosts as you want, though the $5/month price goes up if your network traffic becomes real.

Perfect if you're a sysadmin at heart and not afraid of installing everything you need.