There have been many posts on this topic, I know. But: this is from a personal point of view.
The Bubble Necklace
Ebay or Etsy
I chose the steal. I ordered one off of eBay from a US seller and it was fairly inexpensive. I can't justify spending $150 on costume jewelry. The one from eBay might not hold up as well, but you could buy like 7 from the price of one J.Crew piece.
Have you joined in on this trend? Do you have a real or a fake?