不限流量的正规空间商，是不存在的。
虚拟主机的一个空间，是指你在服务器上的硬盘，开的一个空间，在容量上，占硬盘资源；在流量上占带宽。带宽所支持的流量与要缴的带宽费用成正比，最大支持的带宽越大，要缴的款也就要越多。
为何要限制一个空间的流量？
因为一台服务器会分多个空间，为了公平，才限制流量制流量，否则就可能你一人的流量带宽，占了大部分，导制别人网站访问速度放慢。
The Truth About Unlimited Bandwidth
Web Hosting is a commodity. The main elements of any web hosting plan are disk space and bandwidth. Disk space is the space you have allotted on the web server to store your website. Bandwidth is an amount you have available to transfer web pages from the web server to the browsers of visitors to your site. Web pages and graphics consume bandwidth or capacity on the web. Bandwidth and disk space cost money.
The network lines that carry data around the web (optic fiber, cable, copper wire etc) have a finite capacity. There is a limit to the amount of data that can be transferred at any point in time. Likewise, the hard drive of a web server has a limited amount of space determined by the physical size of the hard drive.
Many hosting companies claim to offer "unlimited" plans (both disk space and bandwidth), but be aware that there are physical limitations to both disk space and bandwidth. Before you buy an "unlimited" plan, know what you're getting into.
The Attraction to Unlimited
When consumers decide they want to place a website on the internet, they are often unaware of the fact that there are limitations. Unlimited is attractive because it requires no further thought. If it's unlimited then I never need to worry about running out right? Although this is understandable, there are risks with purchasing unlimited plans.
The Unlimited Myth
Many web hosting companies offer "unlimited" as a plan feature. It is impossible for any provider to actually provide an unlimited amount of bandwidth or disk space. It's just not possible.