What I do about high gas prices is simply drive my 110 mile per gallon motor scooter almost EVERYWHERE. I also have my old Suburban, which is only driven during rain, for long trips (where it gets 16.5 MPG as opposed to the 9ish it gets in town), and when I have to take passengers.
I actually stretched a tank of gas in the burb out for over 2 months before filling it again (note, I had a 1/3rd of a tank left when I filled it). It would have been even longer, but my scooter was down over a busy weekend that required me to do a ton of driving.
On most vehicles gas is only a small part of the operating cost, most people will spend much more on insurance, repairs, taxes, depreciation, replacement vehicles and other miscellania then they will on gas.
Lets say you have an older gashog vehicle worth around $2000.
Lets say it gets 18MPG and you drive 10,000 miles per year.
Lets say you sell it and buy something that gets 28MPG
Cost for advert. $25
Sales tax $150
Inspection $30
Random repair needed to pass inspection $100 (90 percent of the private partie older vehicles I have bought have needed some random minor repair to pass inspection).
License plates $40
Miscellaneous vehicle change expenses (driving around to do it, washing the old car before you sell it, oops my old cupholder doesn't fit, gotta buy a new one). $20
Cost to switch vehicles (ASSUMING both cost equal insurance, which isn't always true, in recent memory I have owned a large V8, a medium V6, and a small 4, the small 4 had the highest insurance), is $365.
Ok, gas is $2 per gallon in this experiment. 10,000 miles will take 555 gallons in a year, at a cost of $1111 in the 18 MPG vehicle.
In the 28 MPG vehicle 10000 miles will take 357 gallons at a cost of $714
Difference in fuel prices for one year. $397
It takes an entire YEAR to get on top simply from switching from a low gas mileage vehicle to a decent one. And that is with a $2000 car, which might very well not last longer than a year or two.
So, lets do it with an $8000 car.
Cost of advert. $25
Sales tax. $600
Inspection. $30
No random repair on this one, we will assume it is OK 100 percent.
Plates. $40
Misc $20.
Cost to switch vehicles. $715. Also note that it will take you A LOT longer to sell an $8000 vehicle private party. If you do ANYTHING involving a dealership then add $1500 to your cost, as your trade in is gonna be at least $750 below private party value, and the dealership will certainly charge you at least $750 over private party value.
Ok, same gas prices, difference in fuel cost per year is $397. It will take you two years to come out ahead on a private party sale, if you trade it in then it will take you 6 years to come out on top. Will that car even RUN in six years?
Note, I did not even factor in repairs, depreciation, or anything like that, but in general the larger engined cars do tend to last a lot longer, especially with American models.