I Am 85 Years Old With PMR, Diabetes 2, And

I am 85 years old with PMR, Diabetes 2, and AML Leukemia. I'm looking for an over the counter med that can handle a continuing drippy runny nose which, as soon as I blow it, starts again. I don't have a cold or temp but do have COPD (which I've had most of my life and appears to be hereditary). I want the least expensive, non-prescription med I can find that has the most pills for the dollar spent that doesn't have any negative effects. What can you suggest?