Price installments drop down menu in product

[Iriathen]

Hi there..

Can someone help me in creating a drop down menu in every product, where the customer by choosing number of payment installments an interest rate will affect the price. This will only be informative so that customers can choose better ..

Can someone give me a clue how this should be planned?

i attach a link to something similar..

 

http://constantinestore.gr/el/nike-kids-running/5547-nike-tanjun-tdv-818383-011.html

 

Thanks in advance