Medicare begins a major change next month that could save older diabetics money and time when they buy crucial supplies to test their blood sugar.

On July 1, Medicare opens a national mail-order program that will dramatically drop the prices the government pays for those products but patients will have to use designated suppliers. The goal is to save taxpayers money but seniors should see their copays drop, too.

About half of the 4.2 million diabetics with traditional Medicare coverage used mail-order last year. Starting July 1, patients can also get the savings at drugstores enrolled in the Medicare program.

It's the biggest expansion yet of a larger initiative that's predicted to save billions over the next decade by cracking down on waste and fraud in the medical equipment industry.