Not exactly
Would have to be 5 AAs. Most simple voltage regulators (like this one) require the input voltage to be at least 1.5 or 2 volts higher than the output voltage.
214 publicly visible posts • joined 1 Feb 2012
"If you can find such a thing for sale, I'm sure you could find a charger for sale."
$0.54 (34.13p) on Mouser.com (part #512-LM7805CT)
$1.25 on SparkFun (http://www.sparkfun.com/products/107)
And, for the U.S.:
Probably very expensive at RadioShack
But like you said, most people will not have these in their house right this very moment.