I've already talked about opting for generic versus brand-name prescriptions to save money. If you're taking a maintenance prescription, for a chronic condition like asthma or high blood pressure, an excellent value is using the mail-order prescription option.
The model for mail-order prescriptions seems to be the same: to entice people to use the service, you can get a three month supply of your prescription for the price of a two month co-pay if you were to get it at your local pharmacy in person. Essentially, you get a month free. That's quite a savings, especially because the prescription co-pay world never has sales!
Furthermore, it saves you a trip (or three) to the pharmacy, because it comes to your mailbox.
You do have to plan a little, by asking your doctor write your prescription for at minimum a 90-day supply, but that's about it. You mail in the prescription (they pay the postage), and voila you're saving money. Refills are handled over the phone, just like at an in-person pharmacy.