Pearl Paradise is a great resource for classic pearls strands -- also the Pearl Outlet http://www.thepearloutlet.com, Pearls of Joy http://www.pearlsofjoy.com, and Pure Pearls http://www.purepearls.com -- these are all very reputable companies and you will get much better prices than in a regular jewelry shop.
Just a little warning about Etsy -- they are having a big problem with resellers and are either not taking it seriously or looking the other way because it makes them money, who knows. People buy wholesale from manufacturers and then turn around and sell those wholesale goods on Etsy at a huge markup, claiming that the pieces are handmade. This is especially a problem in the bridal category. For example, here are some earrings sold on Etsy http://www.etsy.com/transaction/26812255 and here is the wholesale source for them http://www.orientaltreasurestr.....rings.aspx This kind of thing runs rampant at Etsy and it's one reason why I hesitate to recommend Etsy anymore as a good source for handmade (even though I have an Etsy shop!), at least until they clean up their act.