To make it short and simple, an incandescent needs more power to heat the tiny wire inside (element). A CFL has a small balast, like you would see if you were to take apart a shop fluorescent fixture..but MUCH smaller(it consumes a LOT less power to make it work). A CFL can vary between as little as 5 watts to who knows....
But just for argument's sake, say we have a 26watt cfl vs. a 60 watt traditional incandescent bulb..
ok, so an incandescent bulb lasts 750-1000 hours, fluo 6000-15000!!!!
incandescent costs say, idk, a dollar, when cfl'S cost maybe 3$
just based on the two above mentioned lines, after 3000 hours, your cfl is now saving you money, cause you'd have already gone through 3 incandescents within that same amount of time. Now, the cfl still has 3000-12000 hours of use left, meaning MORE savings!!!
Here's a great link, ( http://en.wikipedia.org/wiki/Compact_fluorescent_lamp ) it can explain in more detail what i have summed up, but i have to quote this:
''A household that invested $90 in changing 30 fixtures to CFLs would save $440 to $1,500 over the five-year life of the bulbs, depending on your cost of electricity.'' that's 130$-300$ per year!!! (that's a lot of plants!)
hope this helps convert anyone skeptical, btw, i'm an electrician