A simple jQuery job

When you go to a product page, you see a form like in the attached file. Now, when you select some of the options in dropdown, the total price below should update. Then, when you click Order, a popup should open where the buyer should enter his simple info (name, email, country) and when he submits that - I get all the info (product details with all the options he chose) on my email and he is redirected to paypal where he pays only $100 (not the total amount from his order). My website (under construction) is static and uses jQuery and Bootstrap (v3.3.7). The theme I'm using has a form to mail function in its PHP files. So, it's a quick and easy job ...