Is there an opensource eCommerce that doesnt make customers register b4 they purchase

Drupal and Ubercart Shopping Cart are free and open source

Ubercart will let you have anonymous buyers purchase and checkout, a user is created for them in your website database silently

 

You can use magento,it's no need to register.And it is practical.

 

try to use prestashop friend, its absolutly free

 

I would recommend Magento