Greensboro, NC -- Compact Fluorescent Bulbs or CFL's may last longer than regular incandescent bulbs, but they are also more expensive.
Duke Energy has a FREE CFL bulb program but they also have a store where you can buy discounted bulbs in various models (globe, candelabra, flood). The styles on sale change, so check back periodically for what you're looking for. 2WTK found globe lights for $1.30 each! They normally retail for $3-$6. You can find the discount store at the same place you register for the free bulb program.
Consumer Reports did the math on CFL's.
By replacing one 60-watt incandescent bulb With a 13-watt CFL you could save $57 over the life of the bulb.
And get this equation: Consumer Reports tested several C-F-L's costing less than two bucks a piece.
They last 10,000 hours!
An incandescent bulb was less than a buck, but only lasted 1,000 hours.
Based on that, you would need to use 10 incandescent for every C-F-L.