If your medication is in tablet form (not capsule), it is often possible to save money by having the doctor prescribe a higher dosage and have the pills cut in half.
If, for instance, 25 mg of something is $25 for 30 pills, but 50 mg of the same medicine is $40 for 30 pills, by buying the larger dosage you're actually getting 60 days' dosage of that medicine and saving $15 a month while doing so.
Some pharmacists will split the pills for you, but there are also small pill-splitters you can buy (usually somewhere around the pharmacy department) that make easy work of it.
It's important to ask your doctor about each specific medicine. Time-release medicines won't work this way, for instance, because by cutting into them you would cut whatever coating makes it possible for part of the pill to be released into your system at a later time.
Here's a Washington Post story on pill-splitting: