http://www.sxc.hu/ kicks ass for a lot of lower-budget purposes. Sort of open-source photography started specifically because people were pissed at paying recockulous fees for commercial photos.
About 70% of the images are flat-out free/no restrictions whatsoever. Remaining 30% are still free for personal use but have to contact photographer for commercial purposes. Photographer might ask for cash, or just want to know what it's for first, or whatever.
You have to click on the thumb to get to the midsize pic, at that point you'll see the license restrictions at the bottom. You have to register (free) to download the full-size versions.
Unfortunately the photo you described isn't likely to be found on the site. The emphasis on the site is generally more objects than people, and nearly all shots of people are the commercially-restricted ones (no one wants to end up on the side of a porn DVD box).
Worth a shot though. Can't beat "free".