How to give a option to customer, to select package option?
- Normal Package
- Extra Package [5% of product price]
You can create 2 simple products called "Normal Package" and "Extra package". And then make all your other products to be Configurable. Each Configurable product will include 2 simple products mentioned above, and each Simple product will change (or not change) price of Configurable product
you can also use "Custom option", applied inside each product.