There are many of these wireless ethernet bridges to choose from. All are basically the same, and as I said, are sold under various descriptions (client bridge, client mode, gaming adapter). There are even wireless routers that can be reconfigured into a wireless ethernet bridge using either the stock or third party firmware (e.g., dd-wrt/tomato). So lots of options, and widely varying prices.
To be honest, $80 for that Trendnet seems excessive. With some careful shopping, you should be able to find one in the $20-30 range. The only advantage that particular Trendnet offers is 450Mbps (theoretically), but that's probably overkill. You'd still need a matching 450Mbps capable wireless router (more likely you have 300Mbps or even 150Mbps).
I’m not making a specific endorsement (since I don’t own most of these), but here are just a few examples, each with pluses and minuses in terms of pricing, portability, extra features, etc.
http://www.newegg.com/Product/Product.aspx?Item=N82E16833122432 (was $20 a few days ago, price increased)
http://www.buy.com/prod/zyxel-mwr102-wireless-n-pocket-travel-router-and-access-point/225181385.html (was $20 a few days ago, price increased)
http://www.newegg.com/Product/Product.aspx?Item=N82E16833704121 (was $30 w/ $10 gift card a few days ago, price increased).
So timing is everything as far as pricing.