Actually, when I saw such an item advertised on TV, I was a little surprised. I thought it was something so simple that one should not need to buy a complicated product to do it. Besides, sticking a tube/nozzle inside your nose would mean that you should be cleaning it every time before and after use. Bacteria could cause more problem than anything else.
This is a bit more personal than I would like, but I suppose this topic requires it.
Years ago, I love swimming, but that was about 20 million cigarettes ago. I noticed how much stuff would came out of my nose immediately after I got out of the water...
One time I had a cold. I know that cold virus tends to grow in the nose, so I thought it may be a good idea to keep my nose clean (literally). Recalling my swimming experience, that gave me an idea...
I use a simple spray bottle to squeeze bottle to squeeze a stream of water up my nose. I am cheap, I washed out an empty shampoo bottle as my squeeze bottle. That initial spray starts softening things up. I kept the inside of the nose stay moist for a few minutes (while I do other things like brushing my teeth). Then, I do another spray and this time I blow it out. It works nicely. I did not have to make or clean anything afterward. Nothing else goes into the nose but water.
It is even simpler when I am taking a shower. I merely use the shower head to do it. Spray at the start and after I washed my body, do another spray a few minutes later and blow.
I've been doing that every day for decades now. I actually believe the nose cleaning reduces seasonal colds/flu. I have colds very infrequently since I begun keeping my nose clean -- even after long flights. Simple sniffling rarely turns into colds. My cold frequency at most one per two years. All but once I had a cold that lasted long than a couple of days.