you dont ask for ephedrine, you go to the congestion/cold med rows and find "bronkaid." Its a bronchodilator with 25mg ephedrine HCL as the active ingredient. They'll have a card that has a picture of the bronkaid box on it, and you take the card to the pharmacy and they get the bronkaid for you. Even though its at the pharmacy, it doesn't need a scrip, its OTC.
I usually just cough once or twice to make it convincing, but in reality they can't not sell it to you. If they really ask say its for a friend at home with bronchitis.
Every walgreens I've been to has it, go back and check again.