You need to specify the features you require in the template on the basis of the features the cost can be analysed.
A look at templatemonster.com can give you an idea of the normal pricing of templates i.e for non-customised ones... customised ones are higher than those depending on the additional features you require.
You must give the whole details for what purpose, what time , etc.. to the designer and then the cost matter comesup to discussion...
Or better yet, jump up to the buy,sell,trade forums here. Then go to the templates forum. Lots of templates for sale, template designers that can do your job, and more.
depending on what you really want to do and your budget, here is a list of sites that offer templates, some are free, some aren't. www.freewebtemplates.com/ www.freelayouts.com/ www.steves-templates.com/ www.webzonetemplates.com/ http://www.adesdesign.net/php/templates.php just look for web template in google and you'll find a much. If you want to have your own website deigned from scratch then you need to get a quote from a design as it's impossible to tell.