I like to use a combination of essential oils and sachets throughout the house. Sachets work well in closets and tucked into pillow shams in bedrooms, living rooms, and dens. Make sure that it is reflective of your location. (i.e. pine or spruce in a mountain home)
I like to use lavender in my home in Napa. You can find it growing throughout the valley. It is a mild and welcoming scent that appeals to most people. Find a good quality essential oil in a glass bottle with a dropper. I really like SVA Organics 100% Natural Lavender Essential Oil
I put drops on mattress box springs, decorative pillow inserts, and in the bottom of stone vases and pots. Be careful not to put the oil on fabric or wood, as it will stain.
You will be surprised how a drop here and there throughout your home will cumulatively create a fresh and welcoming scent.