I need the customers to be able to choose how many sets he/she want of each label in the “shopping cart”?.
I want the customer to be able to choose number of duplicates in the shopping cart in the manner I have tried to illustrate. It is a box with number 1-9. To change number the customer should press the arrow up to increase and arrow down to decrease amount. The price need of course to be updated in real time. Remember also that the total amount field needs to be updated.
I have also attached a screen shot of how I think the amount of sets should be displayed in webmaster email. It should be integrated the same way for the customer email. 
discount
I need another feature in regard to the multiple set in shopping cart. I need a discount calculation. 1 set = 100 % of the price. 2 set. = 90 % etc. The price setting should be set somewhere in the code easily changeable for me.
Discount will be applied individually for every label, and would be based on quantity of individual label ordered - percent of discount
Example - the price is 18.95 for a normal order. It should maybe be 10% off per label when ordering quantity of 2 labels 20% per label when ordering 3 .
The discount will be applied individually for eash label in the cart - So if you order 2 different label design you do not get a discount, unless you order 2 sets of one design. Then you get discount on those 2 sets of the same label.
Discount table will be stored in a separate text or XML file