About Online Shopping In Asp.net and linq

Can help me about to make online Shopping Website. My query is under:
 
1. How to add cart 
2. how to show product valuein repeater (with Image) 
3. how to process billing.
4. what is way of return process  
 
Please suggest me my database isin linq (No SQL)  so Help me as well as earlier.
 
Thank You