Charging of a website

[Plato]

Hello

Two of my friends (Well people I know at my gym) are asking me to design a Personal Training website for them and I'm not sure how much to charge them!

The site would be similar to these:

http://www.demandfitness.com/default.asp
http://www.playtrainer.com/index.html
http://www.pocketpt.co.uk/

I doubt the HTML/CSS will be too hard but the site looks pretty big in terms of PHP functionality.
I've never done anything this big before but I know I'm capable - any ideas how much I should charge for such a project?
I was thinking perhaps £500. Too high? Too low?

Thanks

[tosbourn]

Give yourself an hourly rate you think is fair and multiply it by how long you think it will take.

Or work backwards, you say £500, if it takes you 50 hours or less you are making £10+ per hour. Not a bad wage!

Personally when I take on something I have never done before I would charge slightly less than my normal hourly rate, simply because you are not used to doing whatever so can't guarantee your work.