Sears sells the entire set of security bits (20-25 or so) for $20 or so.

It's got to the point that my wife will throw away any sears tool catalog or flyer we get in the mail before I know we got it

I found a 6pc set for 9.99, but not anything larger! Don't happen to have a part # do you.. I can sneak in an order online and she will never know

Cheers,
Brad

To be old and wise, you must first be young and stupid.