I can only tell you what I bought, the Panasonic VIERA TY-ER3D4MU at $60 However all things in electronics change rapidly, so today's $60 glasses were $120 a year ago. So check around. Perhaps Panasonic will have new and cheaper glasses for 2013.
Whatever glasses you buy, you'll need a storage case. The one I bought is the 3ACTIVE B005CRQLSG. Very nice at $10