yeah!! you can actually buy big bags of shells on ebay for less than $3 BUT they ship from China sooo they take a long time to get there. And if you're worried about being green and carbon footprint it's not so good.
But yes...99 cent stores and goodwill and taking cheap jewelry apart and turning it into craft pieces.
I hope you DO make a cheap costume! I'd love to see it @corinneiskorean!!!