Desktop application in c#.net project

Desktop application in c#.net

I am preparing a project on wholesale shop mgmt..
I am getting a problem in selling multiple items at different price at same time..

I am not getting , which type of controls or format of controls should i use.. to dynamically enter multiple product items , prices and quantity and get total cost of all values.......

i have used textbox controls for entering upto 10 values .......but the problem is .....

if there are 15- 20 items user have to enter... so how can i dynamically handle them..

and how to enter and retrieve this multiple values from database......

how can i design this form ...........

i have used lblproduct , txtproductname, txtproductprice, txtproductqty, txtprodamt...
i have used lblproduct , txtproductname1, txtproductprice, txtproductqty, txtprodamt...
i have used lblproduct , txtproductname2, txtproductprice, txtproductqty, txtprodamt...
i have used lblproduct , txtproductname3, txtproductprice, txtproductqty, txtprodamt...


how can i design this form in more specific and dynamic way.....

plz reply me the complete solution..........as soon as possible