I bought three of them from www.sainsonic.com , they cost me $72.99.i have to say, they are definitly cheaper than buy a single pair of glasses.
When i received the glasses, I tried them out as soon as I charged them. I had seen both positive and negative reviews on these in other places, but I finally deceided to buy them. I have a Panasonic 65" Panasonic Plasma TV . that is a second year 3D model that Panasonic first put out. It uses infrared to control the glasses and the new models use Blutooth. These glasses work as good if not better than my Panasonic glasses and are lighter and more comfortable than the Panasonic glasses. Panasonic glasses are much much more expensive than these and Panasonic does not even list the model that I have anymore. Also the Panasonic glasses for my TV use batteries and are not rechargeable and these you charge off your USB on your computer. I believe that they are a good investment.
They also stated that the following models are compatible:
Compatible Panasonic 3D Glasses and HDTVs:
2010 3D Glasses
2010 3D Kits with Glasses
2010 3D HDTVs: TC-P50VT20, TC-P50VT25, TC-P54VT25, TC-P58VT25, TC-P65VT25, TC-P42ST30, TC-P46ST30, TC-P50ST30, TC-P60ST30, TC-P50GT30, TC-P55GT30, TC-P55GT31, TC-P60GT30, TC-P65GT30, TC-P55VT30, TC-P65VT30