I ordered 2012 Samsung SSG-4100 glasses from ebay us and got it from a korean seller who ships worldwide. I got 2 glasses for 54$ inclusive shipping. 2012 model works with 2011 tv also(but not for 2010)
Now price has further reduced and 2 glasses available for 44$ inclusive shipping.
Note: It took me just 10 days to get after ordering and did not have to pay any customs duties as the package is very light and value they declared as 20$. It is very reliable and you get it cheapest !!!
I have used them once they feel bulky where as 4100GB are light weight and have universally compatible with 2012 RF transmitting 3DTVs such as Panasonic.
But 4100GB open end design can be a problem a dark room is more preferable.
i honestly don't feel any weight of my 3100gb glasses, but with other open end glasses,which i demoed in the samsung plaza ,3d viewing was much affected !