Trying to find the right Plugins for my ecommerce site

Combination of Subscription, ecommerce, and discount (coupons). A friend owns a music store and has agreed to let me sell his musical equipment and products locally online for him. I need help finding the proper plugin or combination of plugins to create an ecommerce that will do the following:

Phase One

#1 Inventory – He has thousands of products, so it would be nice if I could upload inventory initially from excel file (which he can provide). But can do it manually if need be. Once inventory is uploaded maintaining inventory would be more a matter of quantity and price updates and not so much new or different products. (As he sells about everything) Inventory would include photo, description, code, suggested retail, (typical ecommerce stuff), but also online comparison price, & then member discount price. It would be nice if these could be computed for me.

#2 Membership Coupon or Discount – As mentioned above, members would get a special discount price. To provide incentive to buy through me exclusively, I will offer members a percentage of my commission as a discount. Purchases are only local, so nothing will be purchased online, instead when they select a product (click buy) a coupon will be produced that will have a member number, a product number, and a unique transaction number. At the same time an email will be sent to them, me, and the store letting us know a purchase was made. The store would to hold the product for the customer. The customer will take the printed coupon to the store for the purchase. I will need to track this data. I can either track it through a membership program, ecommerce program, or I can export the information track it offline, but it has to be captured. And like any membership program I will be capturing email and other information on the customer as part of the upsell of product.

#3 Articles (the blog part) – As a member customers will have access (and input) to instructional how to articles and videos that I will be creating for them, so the sight will need this ability as well.

If Phase One is successful, we will determine if we want to sell onine and ship… that will be Phase Two.

Sorry for the book, but I’ve researched all kinds of different systems, configuations, and plugins for a number of months now and I either don’t understand a lot of the information, can’t find what I’m looking for, or have to commit to buy something to get the information I think is there but not sure. I’m still learning, I know enough html and css to be dangerous, yet somewhat comfortable with it. Know very little about php or jquery, but learning. Don’t mind going premium, but budget is minimal.

You’re help in pointing me in the right direction would be greatly appreciated.