2 dollars a bulb is more than I can afford today.
Just replace one at a time.
Here’s a conservative estimate of what you will save over the life of each CFL light you replace.
The typical life of a CFL is at least 6,000 hours (typically 10,000 hours).
Let’s say your electricity costs $0.10 a kilowatt-hour. Here in California it is significantly higher than that.
A standard inexpensive 60 watt incandescent bulb lasts about 1,000 hours and costs about $0.80.
So to operate the standard 60 watt incandescent bulb for 6,000 hours the total cost is:
Quantity 6, 60 watt bulbs @ $0.80 each = $4.80
Electricity for 6,000 hours x 60 watts @ $0.10 kilowatt-hour = $36.00
Total cost for 6,000 hours operation of a 60 watt incandescent = $40.80
Quantity 1, 15 watt CFL @ $6.99 (rated 10,000 hours)
Electricity for 6,000 hours x 15 watts @ $0.10 kilowatt-hour = $9.00
Total cost for 6,000 hours operation of a 15 watt CFL = $15.99
So for each 60 watt incandescent bulb you replace with a $6.99 CFL you will save $24.81 over the life of the CFL.
The above estimate is very conservative. The life of the CFL is likely longer and the electricity likely costs more. And that was using a higher quality CFL at $6.99 each. A 15 watt CFL is also brighter than a 60 watt incandescent (unless you buy a halogen which is significantly more expensive)
Replace 100 watt incandescent with 23 watt CFL's and your savings are even higher.
For every one you replace you’ll save. It adds up...
If one can’t afford to spend $7 to save $25, then one will likely remain poor.