Intergration

Question

Mahindra is our client from mumbai (Kandiwali), They have url like www.mahindrapowerolhups.com

In product page have four Items like Hi Speed,Eco Series,Intelli,Higher Range of ups,Inventer Battery. Just want on this product a Buy Button.
After that going ahead a New Page which will be List of Product.
In Product list like Product Name,Model No, Qty,Total, After on that page has Sub total,Shipping Charge and also Total. After click on CheckOut Button.
After completion of this process redirect a New page which is Shipping Address. Fill all details by customers. after that make a payment process.

Don't want a Login,Registration Form.
Product List,that will be alway fixed (Four Product we have mentioned above).

Just give me a Integration Code with Asp.Net (C# )Application.

Please help me.