Those charms on lobster clasps can be found anywhere at the moment (at least here in Germany). And they can be quite pricey depending on material and brand name.
Why spend a lot of money on those charms when you can make them on your own?
It is so simple - I almost didn't dare to post this how-to... And if this has already been posted, I am sorry, but I could not find it when I searched.
The costs depend on what materials you use, but my sterling silver clasp and my shell pearl are probably under 2 EUR.
The second charm was made from turquoise (or dyed howlite I think...) and I added some kind of frame by wrapping around some more silver wire.