[PJ]

Tungsten is a relatively inexpensive material, so to speak. So I don't see any reason not to buy it online. (Not to take a shot at OP, just stating the facts..)

I got my ring from tungstenjewellry.com, and I'm not sure where my girlfriend got my dog tag from. titaniumkay.com is also another site to check out. My cousin's girlfriend also got him a tungsten necklace/pendant for dirt cheap off eBay, and he's had it for over 3 years, still in new condition. So if you don't mind eBay shopping, that would be your least expensive outlet.

Search around for a tungsten ball and chain necklace, but make sure it's a spring-clasp that holds the chain together. Tungsten is a very heavy material, and the last thing you want is for a cheap pop-in clasp to break and lose your ring. Having said that, most tungsten chains are pretty heavy themselves.. so they may not be the best for track days or running..