Gas prices are out of control.  After paying TWICE what we used to for the SAME amount of gas, (or diesel) who has money for knitting supplies?

I've seen a ton of gas saving devices out there.  Devices that supposedly increase fuel efficiency, devices that lets your car run on batteries.  I've even seen a device to let your car run on water.

I am very skeptical that any of these work, but I'm tired of seeing advertisements and would rather hear from real people?  Anyone found any legitimate gas saving devices out there?  If so, post them here! (only REAL ones please, let's don't turn this into a billboard for phony products).