I've decided that every time I have a quick tip to make your life better/easier, I'll post a Quick & Dirty blurb.
So, for our first Quick & Dirty, I'm going to help you make your house smell amazing in under a minute a week on the cheap.
Get your favorite scent of essential oil. We usually use lemongrass oil. Flip the switch to your furnace off. You don't want it kicking on while you have the filter out! Pull the filter out. Check to make sure it doesn't need to be replaced, then pour a few drops of oil directly onto the filter. Replace the filter exactly how you took it out (don't put it back wrong-side-up) and flip the switch.
Voila! Now for the next week or so, every time your hvac system kicks on, your home will be filled with the aroma of your favorite essential oil.
If you have your thermostat settings such that the system doesn't kick on frequently, you can usually switch your thermostat onto a "fan only" setting that will distribute the essential oil scent without changing the temperature of your home.