I paid maybe a dollar after using a coupon..it's so annoying. When you're sitting in the peaceful silence of your home, enjoying the silence.... BAM. Out of nowhere you hear the PSSSST of this mechanical contraption go off. Sometimes, it scares me out of my seat because I'm not used to it. As for smell, I never really notice a difference in the room. Even when I'm sitting like 5ft away from it I don't really notice a smell difference.