Air fresheners can be pretty expensive, but you can get the same effect for much less money by hiding bars of scented soap around your home.
Fifteen years ago I found myself in the Southdale Mall in Edina, Minnesota. It was my birthday and my parents had planned a scavenger hunt. One of the items each team had to acquire was a bar of watermelon soap from Bath & Body Works. Even though my team lost, we got to keep a bunch of the stuff we found along the way. Somehow I ended up with a bar of watermelon-scented soap.
I wasn't aware watermelon actually had a scent, but it was kind of nice. Nonetheless, I was a 12-year-old boy at the time so I wasn't exactly interested in keeping it around. Like most things lost, it ended up behind my bed. After a few days my room started to smell really good. It took months before I realised it was the soap, and ever since I've hidden soap around the house to keep things smelling nice. It is especially effective in drawers and closets because the space is smaller and closed off.
Hiding soap is easy to do. You just leave it in the package and rest it somewhere out of sight. If you don't have anywhere to put it, you can buy foam mounting squares and adhere the soap to the wall. This makes removal easy and they're surprisingly strong, so you don't have to worry about the soap falling off. I've found that one bar per 100 square feet tends to do the trick, but you may also want to hide an extra near your kitchen garbage can. I've found this method to be much cheaper than buying air freshener, especially because you almost never have to replace the bars of soap.