why charge exorbitantly for drugs

Today I would have to comment about the exorbitant prices that is usually charged by medicine dispensers or simply pharmacists.  Many at times I have seen following my thorough investigation that prices of medicine is charged according to how the pharmacist thinks or rates your intelligence. Many at times are poor people who fate has conspired against them since apparently they are the ones who are prone to falling ill and thus they must purchase medicine.
This is a worldwide concern which must be addressed intelligently so that the loopholes that necessitate such merciless acts must be sealed in one way or the other and as far as I am concerned governments cannot do that since intense lobbying by the culprits will scuttle any good intended measures.
For instance, someone purchasing a drug that costs $2 may be charged $4 by unscrupulous pharmacist and it especially affects the drugs of the "last resort" like augmentin, cipro etc. What I need is suggestions on how to curb this loathsome behavior since its' effect is that a family or a person would be forced to ignore a pressing need like paying school fees for a child, purchasing a decent meal etc so as to get the drugs which is essentially unnecessary.
Is there any suggestions?