Assumption : A customer added a mobile phone worth ₹2000 to cart Situation : Our client wants the customer to select one recharge amount for eg. ₹100(from many available recharge amount eg. ₹50, ₹100, ₹150, ₹200, ₹250) in cart, these amount can be added from admin backend. And the final price of product is ₹2100. (for each product customers have to select the recharge amount seperately) Modifying the price would reflect in many areas like invoice, email exchange, checkout total.
In which module the price calculations are there? and whats the better way to achieve this?
Any steps to do this or a sample piece of code would be much appreciated.