What do you think of Online shops which use Cryptocurrencies?

Greetings everybody! I've some questions regarding online shops (where you can shop (only) with Cryptocurrencies). I would like to try one, but first I need to hear someone's opinions and thoughts:1) How do these online shops work? Do they work like Amazon?2) What can you tell me about shipping costs? Will they also be in Cryptocurrencies?3) What is, on the base of your knowledge, opinion and experiences (including past ones), the best (and safest) online shop where I could shop with Cryptocurrencies? via /r/CryptoCurrency http://bit.ly/1FI4H9F