Assistance Creating an Online Software Store

My client wants to launch an online software store that would be a blend of iTunes, [login to view URL] and GlobalSpec. ? He currently has under 1,000 SKUs (individual products) but he plans on offering much more. ? He also plans to sell advertising on the site.? Whatever we develop for him, it needs to be able to manage software downloads and provide auto-responder emails as part of the platform. The entire system needs to integrate with Quickbooks. ## Deliverables I need an estimated cost for this project first in order to get the client to approve the project so we can move forward. ? Please be comprehensive in your pricing estimate. If you bid, please also provide at least two other examples of similar projects you've worked on and budget estimates of what it cost for you to produce your part of the project.