I want to write a cart to give it away.
I see php knowledge is not sufficient but accounting knowledge is required too.
Question:
In cart they may choose main package. each pack may or may not have an addon and/or an extra pack too. the diff. of addon pack and extra pack is that the billing cycle of addon is the same as main pack but the extra pack is one time anyway.
so how to handle tax on cart?
I set a tax for main pack but it will be applied on subtotal of all main pack (+ addon + extra pack) by puuting addon and extra within paranthese I mean they might or might not be chosen on cart. so if only main pack is chosen tax will applied on it only.
But I guess this is not the correct way of applying tax? how about for renewal time as there would be main pack and/or addon pack only as extra pack is removed on renewal time as this one is one time? so for first order apply tac on subtotal of all these three and on renewal time applying it on just two items?
and how to show/list these items with susbotal and applied tax on invoice page?
any advice is appreciated.