Which is the better module for shopping cart? I would like to use a shopping cart module in my site. 

Can any one suggest which would be the better one with basic functionality like displaying content (media), cost, adding to cart, billing, etc. It must include all necessary features of a shopping cart.

Will Ubercart fulfill the basic requirements?
From the sounds of it, you actually want a whole e-commerce system, not just a shopping cart.

Ubercart will do this for you, but the general trend now is to go with Drupal Commerce (project page | Commerce homepage).

Both modules will allow for shopping carts, as well as integration with a variety of payment service providers.  I'd personally go with Drupal Commerce.  It seems a little more difficult than Ubecart at first glance, but once you get over that you'll realise it is much more flexible/powerful.

Try using the Commerce Quickstart installation profile to get yourself familiar/started with it.

There are a lot of good videos for Commerce as well such as Selling Content with Drupal Commerce using Content Access and Roles from the Commerce Guys.

Lastly, there is a blog post here that weighs up the pros and cons of each system (although it is from 2011)

Edit:

You might find the getting started guide useful also.