MSN has a helpful article on saving money on your prescription medications by splitting pills:
In pill splitting, patients cut larger-dose tablets in half to double the amount of smaller-dose pills they receive in a single prescription — for example, dividing 40-milligram tablets to create twice as many 20-milligram doses for the same price. And since drug companies and pharmacies don’t usually double the price of medications as the dose doubles, that can mean lower overall per-pill drug costs and fewer drug store co-pays for consumers…
[Cholesterol-reducing] statins tend to be good candidates for splitting, the researchers noted, because they linger in the body for a long time, and any impact splitting might have on their action wouldn’t greatly alter their effects. The authors cautioned, however, that not all pills can be safely split. For example, those that pass through the body rather quickly, or have special time-release coatings, are not good candidates for splitting.
After the six-month randomized trial, 89 percent said they’d be willing to continue splitting their cholesterol medications in exchange for a 50 percent reduction in their prescription co-pays, the study found. A survey returned by 109 health plan members found that 59 percent would be willing to split medications for as little as $5 to $10 in savings per prescription.