the bungees i know are from razer, steelseries, apuri, hotwire and some clones. razer suppose to put new one in the market, but considering the uncertain release date and the ridiculous "brand value" i would keep away from it. razer also has armadillo 2 in the market. you may find ss mouse bungee on ebay, but if you know some guys in mechanical shop, you may make one by yourself which is not so hard and i know one of my friend get a clone one. roccat apuri looks cool and comes with a 4-port usb hub, but just as speakeasy said, it is an overpriced disaster.
hotwire( or hotline named on ebay) is a chinese brand which is easy to get on ebay that Bilbin shows. also qtan is making group buy now, and you may get one depending on if you would like to order any other stuff to save the shipping cost. on taobao, you could find some clones of ss and razer's bungees also but shipping is still a harsh.
anyway, if you wanna find one in the market, hotwire's might be the budget one unless you could make one.