Ask HN: Pricing plans with hosted applications

Currently I'm building a service that allows people to easily create their own website. The website will be pre-filled with content. The only thing the customer has to do is market their site. All sites will have the same subject, but can't get into detail on this.

While developing I had a lot of thinking about the pricing plans, but that's where I get some doubts. How do you define a good pricing strategy?

I want webmasters that enroll for a plan don't have to worry about scalability and server infrastructure. If they pay the price they now their good.

Now that's where to problem shows up. There will be sites that have low visitors amount ,but on the other hand there will also be sites with a huge amount of visitors (talking about close to a million).

When thinking about pricing plans you have to think about costs, profits etc. But how do you calculate things like traffic when you don't know how much traffic a site would use? Because the sites are hosted and developed in house, we know that like one visitor takes up close to 1MB/Bandwidth.

I would create my pricing plans based on features the website supports, but not on traffic. I'm wondering if it is possible to have a fixed price for this and still make profits?

The reason why I don't want traffic etc in the pricing plan description? Because I want high level users that don't have a clue what 10GB of traffic means to be customers as well.

Please share your 2cents on the problem. What would you do? Any tips / articles are welcome!

Thanks!