Search ads aren't worth the money for me. You should work on your titles and tags though. You probably aren't being found much. Try to put the most important words in the first three words or so of your titles because those are the most important for Etsy searches. What the product is should be in there - cell phone charm, iPhone cover, etc. Try to vary the first words somewhat for different listings.
For tags, multi word phrases are generally better than single words. Try to think of what someone looking for phone charms like yours would type into the search bar.
Also, you should probably work on your photos. Some of them are a bit busy and others are somewhat confusing. I thought you were selling jewelry at first because of the hand mannequin in the shots. I think that the ones that actually show the charm on a phone without all of the other items are the best.
http://www.etsy.com/listing/105263170/iphone-dust-cap-with-hello-kitty-charmGood luck!