Just for you!
Take a look now...
The $500 sitting fee you were quoted by whomever does seem a little steep, the highest I found for this spreadsheet was $400, but that at least included a CD with all the images. Looks like sitting fees can be as low as $100 (one I saw was $65 for a short session) and as high as $300 - $400.
I think it makes a big difference if you get a CD.
Re: *maru0808* I've added pricing info to the photog spreadsheet