Shopping/Deals site survey

We are developing a new website for Finnish/EU use to ease the shopping experience on the net. Now we need you input to push us to the right direction with our sites development. Feel free to go crazy with the ideas, but keep in mind that this is a website not a spaceship or other advanced techtoy. We would like to know stuff that u usually like to buy over the internet, how do you compare, do you buy from Finland, EU or outside-EU and is the total price the reason or trust for the seller. How about shopping coupons, would you use them to get the stuff cheaper and where do you get your coupons now? Do you use adkillers or other browser plugins to get rid of the Ads?