Hi Gaurav,
It is possible to create free text shopping carts only in the new SRM UI. But in that case, you are not using the 'cross- catalogue' functionality offered by the new UI. This functionality is one of the best features of the product.
Follow the config guide to do the basic configuration for the new UI (like number ranges, SICF, etc).
The document might help you get a feel of the new UI and creating a shopping cart in it.
http://scn.sap.com/docs/DOC-54889
Hope this helps 
Cheers,
Yateesh