Find free use photos with Flickr Creative Commons
Find photos that are free to use (with some restrictions) through the Flickr community.
If you're on a really tight budget, but you would like to use nice pictures on your website, or in ads, or just for party invitations, you can still get access to free photos while honouring a photographer's rights.
Photo-sharing website Flickr offers a nice search option so you can search its service for pictures that the photographer has declared as available for free use.
Hit flickr.com/creativecommons and you can explore the site based on a variety of use permissions. Some will be free for use as long as you aren't using the picture for commercial gain, others will say they are free to use as long as you give clear attribution to the original photographer.
Make sure you understand the various licence terms on offer, and from there can soon be using great pictures without it costing more than a link.