How much to charge....larger flash project

hi folks!

I’m relatively new to flash/php/mysql construction. I’ve done a few such projects sucessfully, having passed the initial learning curve.

heres the question:

How dificult would it be to build a flash website with optional user log-in. the purpose of logging-in would be to purchase songs, images etc, and grant ‘access’ to these purchased goods anytime the user logged back in to the site.

I understand the role of the .swf, php files, and MySQL database as it applies to the idea above. i think i have a good idea of how it will all work…

before i agree to the project, and get to work…
Is there anybody out there that has done something similar and might be able to give me an idea of how intense an undertaking it would be, and/or how much i should charge for such a site?

to give an idea of the scope of the project:
-meticulous graphic design… see image…

http://www.the-abstract-life.com/drop_box/full.jpg

-pretty straight forward information presentation…
-custom image gallery…
-rss feeds for image gallery and articles
-custom flash based PayPal shopping cart…
-custom mp3 player with podcast based playlist…
-newsletter
-possible live video feed (for e-concerts) through www.streamingMediahosting.com or the likes…
-the onsite user log-in and purchase tracking to enable/disable content according to user purchases
-custom flash based content management system for a client with little computer know-how (basically a way for him to maintain/edit/upload content without knowing the first thing about a website).