You can get loads of different templates for free on the internet by googling for "free web templates".
I would recommend doing this first and having a go at customizing before you pay someone else, at least you'll know what you can and cannot get for free.
If you know what are doing and can easily edit/customise the code then you should be fine. But if things go pear shaped and you need a designer to fix things don't expect too much help
If you click on CONTEST you can set up a competition for a website design. I don't have personal experience of this but a friend of mine is contemplating it for his website.
Be wary of sitepoint. It's a great site for tutorials, articles, etc but the 'Competition' section has been getting a lot of stick on this, and other Irish forums.
I'd be surprised if you get any kind of unique or well designed layout. Anyone with that kind of talent will not be hanging around 'Competition' sites to ply their trade.
I used http://www.templatesbox.com/ and got some good templates which I got the company hosting my e-mail to work on and develop a simple but effective website.