There are less expensive models of this brand on other websites. Plus, I believe Fellowes was also making a copy cat version because I've used their filters a time or two in my Winix units without any problems but that may have changed now.
Also I use the aftermarket filters (hepa and charcoal) which are much cheaper and do not have the antibacterial treatment which I also seemed to have issues with.
Of course, it's important to make sure you are using all fragrance-free cleaning products as much as possible because the fragranced versions have silicones and chemicals which are added to coat things well and make the fragrance linger and they really, really do linger. Perfumes too, which I've read that the perfume companies make to be neuro addictive, should be removed from the home as well.
Anyway, I hope you can find something that works. Be aware that new products (even air purifiers) will often off gas for a while too. Though I don't remember noticing any with the Winix units that doesn't mean she wouldn't though.
In addition to air purifiers, which should generally work to reduce odors in a large area, it might help to use baking soda for small, confined spaces (cupboards, refrigerators, even small closets) whose air supply doesn't mix much with the larger air volume of your home. It's got a very low 'startup cost' - you can buy a couple small boxes (they often are sold for this purpose and have a panel you can tear off instead of needing to open the box normally) for a couple bucks each and see how it works.
I would HATE nose-plugs. Ugh! They would completely mess up my breathing.
In my experience, HEPA filters help tremendously, though some are louder than others. I echo @Judee's comments about eliminating fragranced products completely. Smoke, powders (especially containing starches), dust and dustmites, too. Life-changing and well worth the effort!