It not only depends on your geographic area, but also on who, what, and which publication (or if for an ad, what licensing terms your client wants) you're shooting for - and last but not least, your overall operating overhead.

It's also important that you don't push prices so far down that your competition (professionals who depend on their income to put food on the table) won't be able to compete with you anymore.

There are a couple of excellent books (ok, they're very nearly bibles for us pros) on photography pricing, and I urge you to buy and read both of those if you're serious about entering the field of photography on a professional level:

1. Pricing Photography, by Michal Heron and David MacTavish

2. Focus on Profit, by Tom Zimberoff

A good starting point would also be a talking to your local camera club or photographers association to get a better sense of rates in the L.A. area (which I know are higher than in other cities around the country).

I hope this helps - if you have any additional questions, please don't hesitate to post here again or email me directly.

- Simone