If these are the two cards you are talking about, along with a difference in clock speeds there is the difference in cooling. One has a reference cooler while the tf has an aftermarket cooler.
Depends what $30 is really worth to you and the applications you are running. Typically a minor clock difference will not make a difference. I don't know which cards you are looking at though.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127745
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127744