yeah big stock photo agencies charge an arm and a leg for using their photos.
but there are lots of cheap royalty free stock photo CD's and places where u can license an image fairly reasonably.
check out
http://www.hemera.com u can pay them a monthly subscription, like 20 bucks, and have access to their library of stock images.
lots of designers in this biz put some pretty big companies at risk for lawsuits by using mainstream stock photography taken from very big stock agencies like Corbis and Getty.
i'm no snitch unless somebody gives me a reason to be
