There are thousands of ecommerce blogs but they have to be self-hosted and not a blogger,blog.
You need to register a suitable domain name and have it hosted on say Hostgator. Hostgator has CPanel which includes Fantastico. One of the many free scripts in Fantastico is WordPress and can be automatically installed with easy to follow steps – you might just have to update it to the latest version which is an easy process.
There are lots of free WordPress themes available in either 1.2.or 3 columns. We find a 3 column theme most suitable for ecommerce.
There are many ecommerce plugins with the WP e-Commerce plugin from http://getshopped.org is easy to install and set up as well as adding new products.Paypal is one of the payment processors included. It can be used for both physical and digital products.