From Bill:
If you have the 15x8 aluminum wheels, get McGard wheel locks P/N 24193 (Summit Racing P/N MCG-24193). I ordered a set from Summit Racing for $16.95.
From Bob Tom:
You're looking for the kits with the 1/2 x 20 R.H. ones. The Tough Locks and Tough Nuts are sold separately in Canada. Try SummitRacing or Walmart in the U.S.