Flavel, as lisa said, you first step is to figure out what niche or sub-niche you're going to target, what products you're going to offer, which merchant or affiliate network you're going to target and so on.
To be honest with you, building stores, eCommerce and logistic websites is a thing of the past. I'm talking 1998-2000 dot com boom. Unless you have a physical store and want to expand your business and bring it onto the virtual market or you have millions of dollars to start-up a new virtual store business.
For an average guy, there two proven ways to make money online, affiliate marketing or freelancing.
The first way is the most rewarding, secure and a better choice as a business.
Now, affiliate marketing could be done in many many different ways. Have you heard of online deal/coupon sites? These sites offer deals, discounts, rebates, coupons and freebies to their visitors to save money. One such example of site is bensbargains.net. This site specializes in finding discounts, deals and coupons on electronic products. Similarly, there are deal sites for clothing, shoes, etc.
So with what you and your friend have in mind, i think this is something you can look into and explore. Again, you need first pick a niche you want to get into and then go for there.
Hope I didn't confuse you
