In case you are trying to tighten your belt literally and not just by saving money Calorie Lab might be the place for you. It is a database of calories for common restaurant and prepared foods.

While it does not have calorie counts for common foods like an apple, 4 ounces of chicken breast, etc. it does have information on Big Macs, Krispy Kremes, and Cokes -- all of which regularly show up around my office unfortunately.

 http://www.downloadsquad.com/2008/08/27/stop-check-that-snack-on-calorie-lab-first/

When ever I get in the mood for fast food I look at calorie king's site.

It doesn't take long for me to not want it any more.