If you're not planning on spending much, your best bet is this Chan Luu Pendant. It's a wonderful product, while not very costly. Another good option is this Alexis Bittar Pendant. While the price is competitive, be sure that this product will become a wonderful addition to your wardrobe. You might also want to consider this Astley Clarke Pendant. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
If you have enough to afford it, look at this De Beers Pendant - a great luxury choice. While you're at it, also have a look at this David Yurman Pendant. Yes, this item is expensive, but it does not mean it's not worth it. And one more item you might be interested in is this John Hardy Pendant. 'Cause you deserve nothing but all the finer things!