Pricing for commercial photography

[Baldwin94]

I've done some research on yahoo but I'm still not finding the answers that I'm seeking. First of all I think what I'm looking for is how much to charge for "commercial" photography. But I might be calling it the wrong thing. I have a friend that is a real estate agent. Most of her new business comes from her website and she's good at keeping it updated. She wants to do a section on there that breaks down the different neighborhoods that she specializes in. She has given me a list of 40-50 locations to photograph in order to show what the different neighborhoods have to offer. The majority of the locations are a 20 minute drive time for me and some are up to 30 minutes away. So far I have delivered 6 of the photos to her. I have kept good notes on photographing time, drive time, editing, parking expenses. I am new to this and am really enjoying the project. We have a deal between us that we'll do an exchange-I'll do the photography for her and her partner will make a website for me. We are to invoice each other for tax purposes though. I don't know how much to charge! She also said to think about how much I want to charge her if she uses the photos more than once, or for different projects...I have no idea!
Any help or direction that you can give me would be greatly appreciated!!

Thank you,
Joanna

[OsmosisStudios]

Hourly wage you'd like X hours spent + "creative fee" = price.