Why is there such variation between the price of drugs at different pharmacies?

well its really what your insurance will pay but in the long run if you have a pharmacy presciption card it gives you a discount on meds and i see what your saying what the pharmacy charges and another one charges different it goes by what the pharmacys charge and what they actually gets when its all said and done now they have a deal on gernerics 4 dollars and 90 day is 8-10 dollars now the pharmacys want to over charge make profits on theses medications i see that part but i don't see why the over charging cause they only get it when a person can't go with out that medication and some are private