For most pharmacies, the profit margin is 2-3 percent. The profit margin varies based on what is "sexy", how tightly you run your pharmacy, among other things.
For example, filling a script for HIV medications can net you 20-100 dollars per script. You open a pharmacy next to a HIV clinic, you can expect strong profit margins because usually HIV patients have a wide variety of other problems.
On the other hand if you cater to people who have hypertension and diabetes, your profit margin is slim. You might get a dollar for each script and end up losing money after you factor in labor, vial, transmission fees, etc. Of course diabetes patient also spend ~10k a year on other pharmacy supplies such as bandages and sugar free products that a gas station or supermarket might not carry.
It also depends on how tightly you run your pharmacy. Everything costs money. A vial might cost 20-30 cents, labels might cost 30 cents, transmission fee every time you bill the insurance is about a nickel, etc. If you are a pharmacy that reuses the vials, your profit goes up.
Blueclassring, profit margins are that low!!! However it is still nice to go into business because you are your own boss. The statement where you said you put in 100,000 dollars to get 2,000 dollars is false. Although a 2 percent return right now is pretty good, you have to look at how much business you do. Most pharmacies should be able to do a million dollars worth of sales considering that a refill of Lipitor cost 100 dollars, HIV meds can cost up to thousands, etc. A 2-3 percent profit isn't bad compare to other industries. Don't forget that profit is after you pay yourself (maybe 150k considering you will probably work about 60-80 hours a week).