I've only had to buy it in three states, but generally my experience has been that you can buy a "30 day supply" per month. How often are you sick that you need more than 30 days of the stuff every month? If we run out I'll buy a 30 day supply and that generally lasts the whole family a year or more.
You definitely don't have anyone in your family who gets severe congestion from allergies then. The "funnest" form it takes for me is when I start going partially blind in one eye due the the sinus pressure