The Consumer Action Center has been getting a lot of questions about fuel economy boosters. During the energy crises of the '70s, the same thing happened with people selling pills and additives for your gas tank. The EPA now says that you shouldn't fall for these ploys. Out of 100 gas-saving devices tested, only 6 gave a tiny improvement in fuel economy -- and even those were nothing to write home about.
The reality is that you have to do the simple things to get better fuel economy. So unload your trunk, keep your tires properly inflated and slow down out on the road.
Years ago, gas pumps couldn't "read" prices above 99 cents/gallon. So when the price went to a $1/gallon, you actually had to look at a conversion sheet provided at the pump to figure out what you owed.
Now, what's old is new again. Some gas stations around the country can't read above $3.99/gallon. These stations may be forced to change their pumps at great expense, or we'll have to go back to charts on the pumps in states that permit it.
One final thought: There's an assumption that the gas prices we have today are the new floor and we can only go higher. That's called "inertia bias." But economics doesn't work that way. Prices could decline again, but who knows to what level. All bets are off, though, if there's a terrorist attack or war.