In Islam that "BOGO" (By one get one free) type deals are reserved for worshiping aka Haqooq Allah. Yes Allah is Raheem and Kareem. He can give you double or triple or even higher reward for your worship.
thanks for making islam into a franchised SUBWAY, with its various branches like sunnis, shias etc. and everyone has their own special deals.
you know i have a problem with your other statement. imagine if you were playing a cricket and every time you hit a boundary you were given two runs, while the other teams boundaries got four runs for each one. wont that be injustice. now apply the same analogy here. why should God be awarding different amounts of sawab for the same thing? if he is an Aadil, he should not be discriminating between one person or the other.