Reduction of US Medicare part B premiums available?

When I turned 65, my letter from Medicare had something about reducing the basic Medicare part B premium (currently $148.50) under low income conditions. Since I have V.A., I declined part B and paid little attention to those details.

I haven’t been able to find anything online about a reduction from the basic amount, just an increase. But I know someone whose husband paid $148.50 while she paid $137.50. And both are extremely low income, so if there is a reduction available, they should be/should have been getting it.