CFL Light Bulbs 4 for $0.49 at Costco - B&M YMMV
So, even if you've not the biggest fan of CFL bulbs - for $0.1225 a piece it is hard to go wrong.
Found these while browsing the Cosco in Chicago on Elston Ave. today.
4 Pack Feit Electric 60w CFL bulbs.
$5.89 with $5.40 instant rebate from ComEd = $0.49 a bulb