3. Create a ribbon-and-cotton-ball air freshener

A few years ago, Julie of Frugally Blonde shuttled her teen son and his friends to training sessions as the boys prepared for a mini-marathon. The experience opened her eyes — and tortured her nose: “I honestly had no idea boys could smell that bad,” she says.

So, Julie broke out her favorite essential oils and — combined with a ribbon and cotton ball — created a car-vent air freshener. You can see the result on her blog. Julie says:

“They are not only cute, but because they go into the vent they make the car smell better than the hanging air fresheners. Plus they only cost a dollar or two to make.”

Essential oils aren’t exactly cheap on a per-ounce basis, but you can easily find them, say, on Amazon.com and at Target for $5 to $10 per bottle. Julie says she puts only four drops on a cotton ball. At that rate, even a small bottle should last you a long time.