We call it "carpet sprinkle." I think the proper term is "carpet refresher." Whatever it is, I don't use much of it but I do use it a few times a month. I know it's not great for your vacuum cleaner and I also know that they always smell really artificial. Overwhelmingly, nauseatingly artificial.
So I decided to make my own. The main ingredient in most commercial carpet sprinkles is baking soda. I thought it a fine place to start.
Start with baking soda and a scent. You could use essential oils, if you want, but they're expensive and this diffuser stuff works just as well in my opinion.
Sprinkle on to your carpet where you need a bit of refreshing. I tend to lightly sprinkle our carpet every two weeks just to get any sort of funky smell out that has been tracked in. Vacuum as you usually do. This smells much better than commercial brands and you don't need as much.
$.99 for the scent (clearance at Bath and Body Works - we have an outlet store near us)
$.39 for the baking soda
Total = about $1.50 including tax
Not too bad!
If I do it again:
I would use a different scent. The "Frosted Cupcake" scent I used is very nice - kind of a sweet vanilla smell. I prefer something a bit spicier: cinnamon, cloves or ginger. This particular scent was on clearance and you can't beat a 99 cent bottle of scent.