Complex online Order Form with dependencies and PayPal integration

This should be a relatively easy task to someone with lots of javascript / Form experience.... I'm looking for help to create a new online order form. In the past I have done all the website work/coding myself, with some help via google searches when necessary. I'm not advanced enough to properly write the code for my new order form. I can provide the current progress I have made, to give a better idea of what I need to be completed. The form must contain a few key items that I cannot get to function all at once, including; -dependencies (for example; a dropdown menu, which will affect the base price of the product) -item upgrades (will increase product price) -a specific 10% discount option (will affect the BASE price, not the item upgrades or add-ons) -coupon/discount code box (that will support multiple working discount/coupon codes with validation) -suggested product add-ons (these can be affected by the applied discount/coupon codes) -other suggested products (these can NOT be affected by the applied discount/coupon code) -a 'current total' box (so customers can see the price of their order in real-time) -paypal integration (all of this information needs to post to a PayPal cart) I have constructed an image that outlines precisely what I want, with some descriptions as well.. The details do NOT have to be perfect, but the FUNCTIONALITY does. I can tweak and adjust the details if necessary. I will also supply the images for the custom image grid that is shown, and current codework I have if desired - as well as some other examples I have found.