Dynamic value add into 2 variable like comma separated

hi

i need some idea , I am doing one Billing application in Asp.net and SQL Server2008 that Application i want to add dynamic row as well as the value stored in variable like product 1, product 2, product 3, product 4..... then i need to pass that variable to DB.
I want to create multiple row dynamically in front end (EXAMPLE : in that billing system one customer need 2 product another customer need 20 product in this case how to create dynamic text box in front end and also that all the value stored in DATABASE throw the stored procedure ).