How much do you charge for a website?

Charge as much as you can get away with -- and make sure you bill by the hour and start with a reasonable statement of work.

Any time estimate you give you should probably at least double -- freelancers typically get themselves into trouble by quoting either too low an hourly rate, too low of a flat fee, a too low time estimate for completion, or the customer keeps constantly changing what they want...

As a freelancer, I work fast and charge $15 an hour. I can usually make around $500 per website, but I'm not the most experienced web developer.

It really depends on the website. Some websites take half an hour by one developer to make, some take 6 months by a team of 30 senior developers, DBAs, sys admins, designers and managers.