@carriegirl1,
Here is one website with a variety of offerings.
Edit [Moderator]: Link removed
I know that locally (Toronto), I can definitely find freshwater pearl bracelets starting at about $20 each. The nicer ones are between $35 and $50. If you're not paying for your attendants clothing, I'd suggest going for a slightly higher-end gift, i.e. the $35 - $50 bracelet v the $20 version.
$20
$50
I think the difference is noticeable and worth it, especially if they're paying for their own dresses/shoes.