The singer is Ashley Gearing and the song is Back to Blu
Daniel Lee Kendall - Lost in the Moment
It is not a Scion commercial.
Pink Martini is the singer who sings the PC Black Label Martini commercial.
Santa.
Girls with shoes
A stupid bimbo
Cat Stevens wrote the song. Cat Powers sings the song in the commercial.
April McLean - Head over Heels
April Mclean - Head over heels! Love it!
Daniel Lee Kendall - Lost in the Moment
Cat power is the artist... the song is "How can I tell you"
Aquamarine pendants should be available from most jewelry stores like Zales, Hannoush Jewelers, Helzberg Diamonds, Rogers Jewelry, and Riddle's Jewelry, as well as department stores like Sears and Walmart. Alternatively, one can order online from websites like Angara, Amazon, and eBay.
Mary J. Blige sings in that commercial.
The Heavy sings How You Like Me Now from the Kia commercial
Dee Carstensen sings "Silent Night" on the Pampers commercial.
You could very likely find nice bridesmaid jewelry at any of the big box jewelry stores in the area, like Zales, Kay, or Hannoush jewelers. They normally have items in every price range, and one should be able to find something nice that will fit a budget.
The question was who sings the song, not who wrote it.