for hardware i think bitcointalk is best but online
you can use prepaid cards to buy but for sell bitify is better
I dig what you are saying but bitcointalk is not an online shop, it is a forum where people can also offer selling services in exchange for bitcoin. More like just a P2P thing and not on a large scale or even a micro scale.
By online shops, these are pure e-commerce sites that purely sell stuffs and accepts bitcoin in the process as another means of payment apart from debit/credit cards, paypal etc.
Dude he just passed the reference that where you go to buy some products in this forum itself. Amazon plans to starts accepting bitcoin directly in middle of this month. To buy now, you can use the purse.io site which can give you the way to buy things in Amazon. You will get the additional discounts to use the site and make bitcoin payment.