Temperatures here in the Northeast are at the freezing mark or below, so the heated indoor air is very dry. This is a good time to use a saline spray to keep nasal passages moist.
I use a lot of saline spray every winter. My preferred brand comes in little bottles of 50ml (1.69 ounces) and costs about $3.50. That's $2/oz. It doesn't last long.
The first bottle of the season already ran out. So rather than buy
another, I bought the saline solution that's marketed to users of contact lenses. For the same price, $3.50, I got 12 ounces, a whopping seven times more, which should last all winter.
Of course, I don't squirt the stuff into my nose from that larger bottle. Instead, I refill the little spray bottle. I just remove the tip from the spray bottle and pour the saline solution in and then press the tip back on.
It turns out that the cheaper, contact lens saline solution is more soothing than the nasal saline. Perhaps the nasal solution contains more anti-microbial chemicals to keep it from harboring germs. After all, the bottle is inserted into one's nose. With each squeeze, the user could aspirate germ-infested nasal mucous into the bottle. So the producers of the nasal spray would want to ensure that their product won't result in re-infection with some pathogen.
If you decide to try this cost-saving idea, do your best to avoid contaminating the bottles and solutions. Your workspace and hands should be as clean as possible. You can place the spray bottle tip on a clean paper towel or tissue while filling the bottle. Also, don't fill the bottle more than halfway, otherwise you won't get a fine spray when you squeeze but rather a surprisingly strong stream.