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.