Hitachi does a good cheap bit set. Called 752500 - Hitachi 41PIECE IMPACT BIT & SOCKET SET.
Contents :
10 x 1/2"DR. Impact Socket: 8 , 10 , 11 , 12 , 13 , 14 , 17 , 19 , 21 , 22 mm
1 x 1/2"Dr x 1/4"H.Adaptor
1 x 1/2"Dr. 75mm Socket Adapter
1 x 60mm Stainless Bit Holder W/Quick Change
28 x 25mm Driver Bits :
Philips : 1,2,3
Slotted : 3,4,5,6mm
Pozi: 1,2,3
Hex: 3,4,5,6mm
Torx: T10,T15,T20,T25,T27,T30,T40
Tamper Torx : TH10,TH15,TH20,TH25,TH27,TH30,TH40
http://www.impresstools.com/productbaselevel.asp?
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20Holder%20and%20Bits&subtypeid=322&categoryid=-1