This is one of my favorite products! Starter kits go for about $9 and come with the sense and spray, 2 batteries, and 1 (I guess it’s a bottle?) of fragrance.
Once you get it all set up and ready you can test it by pushing the button in the front (make sure the front cover is down)
The cool thing about these is you set them in a room somewhere and their little motion sensor will detect movement and spray a little fragrance in the air- BUT it will only spray once every 30 minutes unless you mannually press the button before 30 minutes.
So if no one is home it’s not spraying all day long for nothing.  But as soon as someone is in the room you have a pleasant smell while you’re there!
Personally I love the Clean Linen scent.  Currently Glade only offers 6scents: Apple Cinnamon, Clean Linen, Country Garden, Hawaiian Breeze, Powder Fresh, and their new one- Clear Springs.

Now for my experiences:
When I first started using these they would only last me a month and when I went to replace the fragrance sometimes it wouldn’t work. I called Glade to report the issue since it was a new product and probably was just a glitch.  They were great and each time would send me a coupon for a new starter set!  What I found out later was the batteries were too low to function properly! They had enough juice to have the light on so I never thought the problem was with the batteries.  But once I replaced the batteries it was working great again!  So now if they don’t work (I have mulitiple of these around my house) the first thing I check is the batteries, by opening the front cover and pressing the button on the front- if the mechanics move down about 1/4 to 1/2 an inch I know the fragrance just needs to be replaced.  If it barely moves then I know the batteries need to be replaced.  It’s been a trial and error thing- but all in all for how much I love the product it’s worth it!

As for coupons- sometimes you can get them from their website.  For a while they were including a coupon for $1/2 for the refills, but I haven’t seen the coupon in the refills I’ve bought lately.

Here is the official Glade Link so you can check it out yourself!
http://www.glade.com/productDetailPage.aspx?productId=23